When market analysts start using words like “craze” and “unsustainable” to describe the state of housing, there may be something wrong.

And when one banking analyst describes the real estate market’s future prospects with the words “ghost town,” there may be something really, really wrong.

StatsCan released its April housing starts numbers on Tuesday, showing a startling 14 per cent jump in the number of new residential units coming under construction.

That went against observers’ expectations of a slight decline in starts, given the recent softening of prices in some of Canada’s biggest housing markets. But instead of a pull-back, Canada saw the second-largest number of condo starts ever recorded in a single month. And Ontario hit an all-time record.

CHECK OUT SOME OF THE WORLD'S COOLEST GHOST TOWNS

No surprise where much of the boom comes from: Condos. Of the seasonally adjusted 245,000 starts in April, fully 158,000 of them were multiple-family dwellings -- nearly two-thirds of the total. While single family home construction grew a modest 0.6 per cent, condo construction exploded by more than 27 per cent over the course of the month, when adjusted for seasonal patterns.

Analysts appear to be in agreement: That’s too much.

BMO Chief Economist Sherry Cooper says housing construction is “well above underlying demand” and the market is “at risk of overheating.”

TD Bank's Dina Cover was more blunt: “We suspect that this level of home starts is not sustainable,” the economist wrote in a note to clients, but added the bank expected the housing market to remain robust for the rest of the year.

Not everyone is so sure.

Scotia Capital economist Derek Holt told the Globe and Mail that there are signs of a housing bubble appearing in key hot markets.

In Toronto, he said, a quarter of the condo stock is sitting empty -- a situation similar to the one in south Florida some five years ago, just before the condo market there collapsed. It’s now possible today to buy a condo in Miami’s once-hot condo market for as little as $50,000.

“This is the ghost city phenomenon,” Mr. Holt said.

UPDATE: The source for Scotia Capital's assertion that a quarter of condos are empty, Shaun Hildebrand, an analyst for the CMHC, has restated that number to 22 per cent. He also notes he is referring to "investor owned" properties, and says it's unknown which ones are or aren't empty."We simply do not track that," he said, as quoted at the Financial Post.

Scotial Capital has also corrected the statistic, saying they "took an overly strong interpretation of CMHC figures." The 22 per cent number refers to the "condos in the Greater Toronto Area [that] are being rented as one portion of the investor owned segment," the note said.

The prospect of a housing bubble creating “ghost cities” is not just hysteria. It’s been on the minds of housing market analysts recently because of the bursting of the massive housing bubble in China in the past year, a market swoon so bad it exposed entire empty cities, waiting for occupants who will never arrive.

Obviously, the scale of the problem in Canada is much smaller. But the idea of empty condo buildings has many people worried about the ghettoization of Canada’s largest cities.

Toronto Star columnist Christopher Hume expressed those concerns in a recent article, in which he suggested the city’s condo complexes could end up being enormous new ghettos.

Hume argued that because condos tend be small, they rely on strength in the low-end housing market to keep their prices up. If a correction happens -- such as the one many predict Canada’s largest cities are in for -- those condos will lose value, will be turned into rental units, and will soon sink into poverty.

Another wild card in Canada’s condo market is foreign investors. By some estimates, investors from abroad have been snapping up as many as half the condos in Toronto and Vancouver. Little is known about who they are, and where their money comes from. So predicting when it might stop flowing is virtually impossible.

But one thing is certain: Foreign investors are crowding the real estate market, and forcing prices upwards. That has prompted some politicians and policymakers to call for a ban on foreign investment in residential real estate, as Australia recently did.

In an article at the National Post, Diane Francis reported on what she described as a tax fraud scam that’s blowing up a real estate bubble. Investors put 5 per cent down to buy a condo before it’s built, then flip the condo for a higher price and pocket the difference -- without paying taxes on this capital gain.

“[Condo] brokers tell me I can flip my assignment and pay no tax and there is no paper trail. They say we do it all day long,” the Post quoted an anonymous investor as saying.

All told, a picture is emerging of a housing market that is being increasingly distorted, and one that has less and less to do with the demand for shelter. If you get into the housing market this year, know the risks, and exercise caution.

CHECK OUT SOME OF THE WORLD'S COOLEST GHOST TOWNS

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• St. Elmo, Colorado

  Getting there: <a href="http://st-elmo-colorado.com/" target="_hplink">St. Elmo</a> is in Gunnison National Forest. Numerous trails for hiking and off-road driving are easily accessible from town.

• Chaco Canyon, New Mexico

  Getting there: A 9-mile paved loop road runs through the canyon.

• Bodie, California

  Getting there: <a href="http://parks.ca.gov/?page_id=509" target="_hplink">Bodie</a> is a California Historic State Park, 7 miles south of the town of Bridgeport.

• Humberstone & Santa Laura, Atacama Desert, Chile

  Getting there: Humerstone and Santa Laura are close to the town of Pozo Almonte, 30 miles east of Iquique, which is the nearest city with places to stay and an airport.

• Bhangarh, Rajasthan, India

  Getting there: Bhangarh is 18 miles northeast of Jaipuir. <a href="http://rajasthantourism.gov.in/" target="_hplink">Tours </a>of the haunted city are available.

• Kayakoy, Anatolia, Turkey

  Getting there: <a href="http://www.gofethiye.com/" target="_hplink">Fethiye</a>, approximately 2.5 miles north of Kayakoy, is the closest town.

• Herculaneum, Naples, Italy

  Getting there: Herculaneum, 5 miles south of Naples, can be reached from the city by bus or train at the Ercolano station.

• Belchite, Zaragoza Province, Spain

  Getting there: The remains of the old town are .5 miles from modern Belchite.

• Kolmanskop, Namibia

  Getting there: The nearby city of Luderitz is a good base for exploring Kolmaskop and other abandoned mining towns in the area.

• The Pyramid - Soviet mining city on Svalbard, Norway

  Pyramiden is a soviet mining settlement on the Norwegian Svalbard territory. Ghost town on 79 degrees north. Getting there: Stay in Longyearbyen, <a href="svalbard.net" target="_hplink">Svalbard</a>'s largest city, and take a day-long boat trip to Pyramiden. Guided tours are available.

• Fayette, Michigan

  <a href="http://www.huffingtonpost.com/social/Geoffrey_Pelkey"><img style="float:left;padding-right:6px !important;" src="http://graph.facebook.com/675650517/picture?type=square" /></a><a href="http://www.huffingtonpost.com/social/Geoffrey_Pelkey">Geoffrey Pelkey</a>:<br />Fayette was one of the typical 19th century "boom towns." The Jackson Iron Company founded the town in 1867 The site was chosen for the limestone, the small but deep natural harbor, and the immense stands of hardwood on the entire length of the Garden Peninsula. (The hardwood was used to make charcoal, which together with limestone, was essential to the iron smelting process.) By 1891 the hardwood on the peninsula was gone and soft coal was replacing charcoal in the smelting process. It was no longer profitable for the company to run Fayette. The furnaces went cold and the town slowly became deserted.

• Hancock, Michigan

  <a href="http://www.huffingtonpost.com/social/emcd"><img style="float:left;padding-right:6px !important;" src="http://i.huffpost.com/profiles/262708-tiny.png?20101115194900" /></a><a href="http://www.huffingtonpost.com/social/emcd">emcd</a>:<br />In the great UP of Michigan, old buinding at the abandoned Quincy Copper Mine museum.

• Tunisian desert

  <a href="http://www.huffingtonpost.com/social/Jacek_Lerych"><img style="float:left;padding-right:6px !important;" src="http://graph.facebook.com/100000307613881/picture?type=square" /></a><a href="http://www.huffingtonpost.com/social/Jacek_Lerych">Jacek Lerych</a>:<br />

• Tunisian desert city (proprely cropped)

  <a href="http://www.huffingtonpost.com/social/Jacek_Lerych"><img style="float:left;padding-right:6px !important;" src="http://graph.facebook.com/100000307613881/picture?type=square" /></a><a href="http://www.huffingtonpost.com/social/Jacek_Lerych">Jacek Lerych</a>:<br />

• Jerome, Arizona

  <a href="http://www.huffingtonpost.com/social/azfooddude"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/azfooddude">azfooddude</a>:<br />The Grand Hotel in Jerome, AZ use to be an insame assylum during the copper mining days.

• Dogtown, Cape Ann, MA

  <a href="http://www.huffingtonpost.com/social/Bill_Way"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/Bill_Way">Bill Way</a>:<br />After the Revolution, the many widows in the "Common Settlement" (now Gloucester) MA moved inland to avoid piracy and crime, and many got dogs for protection. The last survivors were moved to poorhouses in the early 1800s, leaving just the dogs. All that remains are some "cellar holes" lined with stonework, and these boulders, which were carved in the 1930s.

• Real Photo Ghost Girl in White

  Taken in Springfield, IL Dec 2009 Girl in white, woman at right, apparitions not visible when taken.

• Dancing Lady Ghost Apparition

  Cemtery photo from early 2011

• Bodie, CA

  <a href="http://www.huffingtonpost.com/social/Jen_Gold"><img style="float:left;padding-right:6px !important;" src="http://graph.facebook.com/779496339/picture?type=square" /></a><a href="http://www.huffingtonpost.com/social/Jen_Gold">Jen Gold</a>:<br />Definitely check out Bodie, CA - beautiful abandoned mining town in northern CA

• Volubolis, Morocco

  <a href="http://www.huffingtonpost.com/social/Margaret_Reimer"><img style="float:left;padding-right:6px !important;" src="http://graph.facebook.com/1238205470/picture?type=square" /></a><a href="http://www.huffingtonpost.com/social/Margaret_Reimer">Margaret Reimer</a>:<br />Volubolis, Morocco--the farthest south the Roman Empire got, the outpost that supplied fierce beasts for the Games, and that was abandoned after the expansion of Islam into Morocco. Eerie and wonderful, includes some fantastic floor mosaics

• Goreme Valley, Cappadocia, Turkey

  <a href="http://www.huffingtonpost.com/social/Mikecochran"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/Mikecochran">Mikecochran</a>:<br />One of many abandoned villages in Cappadocia.

• Tunisian Ghost Town

  <a href="http://www.huffingtonpost.com/social/Mikecochran"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/Mikecochran">Mikecochran</a>:<br />One of hundreds of abandoned villages in central Tunisia.

• Bodie

  <a href="http://www.huffingtonpost.com/social/horsegail"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/horsegail">horsegail</a>:<br />An old house in Bodie, Ca

• Through the cracks of time

  <a href="http://www.huffingtonpost.com/social/horsegail"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/horsegail">horsegail</a>:<br />THe ruins of Bodie, California

• Eastern State Penitentiary

  <a href="http://www.huffingtonpost.com/social/draffi"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/draffi">draffi</a>:<br />

• Bannack, Montana

  <a href="http://www.huffingtonpost.com/social/JaredMG"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/JaredMG">JaredMG</a>:<br />Bannack, Montana. A ghost town thankfully preserved by Montana's State Park division. Over 50 intact buildings to explore. The gallows still stands, and bullet holes are still in the walls.

• Mogollon, in the southwest New Mexico

  <a href="http://www.huffingtonpost.com/social/rcgauer"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/rcgauer">rcgauer</a>:<br />Part ghost town and part quiet retreat, Mogollon (pronounced "muggy - own") is a historic jewel perched in the Mogollon Mountains of southern Catron County, just north of Grant County and Silver City. Formed as a mining camp and later as a mining community, Mogollon's hills still bear witness to the heavy work of hard-rock mining underground: Mine shafts, rails for mine trains, sluices, abandoned buildings and the ruins of head frames still dot the landscape. Never attempt to enter mine ruins, shafts, buildings or other properties. More at www.silvercityacd.org.

• Royal Gardens Subdivison, Big Island, Hawaii

  <a href="http://www.huffingtonpost.com/social/kraig"><img style="float:left;padding-right:6px !important;" src="http://i.huffpost.com/profiles/34298-tiny.png?20090908232346" /></a><a href="http://www.huffingtonpost.com/social/kraig">kraig</a>:<br />Since 1984 volcanic flow from Kilauea, the world's most active volcano has reclaimed this one populated neighborhood.

• Centralia, Pennsylvania

  <a href="http://www.huffingtonpost.com/social/JaredMG"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/JaredMG">JaredMG</a>:<br />The site of a coal fire that's been burning underground since the late 1960s, Centralia has fewer than a dozen residents today and has even had its zip code revoked by the postal service.

• Elizabeth Town, NM

  <a href="http://www.huffingtonpost.com/social/Nina_Anthony"><img style="float:left;padding-right:6px !important;" src="http://graph.facebook.com/1301880638/picture?type=square" /></a><a href="http://www.huffingtonpost.com/social/Nina_Anthony">Nina Anthony</a>:<br />Old truck pointing the way to Elizabeth Town (aka "E-Town") New Mexico, a once-bustling gold mining town with 7,000 residents. Black Jack Ketchum was supposedly a frequent visitor.

• Death Valley Junction, California

  <a href="http://www.huffingtonpost.com/social/kraig"><img style="float:left;padding-right:6px !important;" src="http://i.huffpost.com/profiles/34298-tiny.png?20090908232346" /></a><a href="http://www.huffingtonpost.com/social/kraig">kraig</a>:<br />This ghost town also houses the Amargosa Opera House, owned by Marta Becket. The hotel next door is claimed to be one of the most haunted hotels in America. It is an old dormitory for miners.

• Rhyolite, Death Valley

  <a href="http://www.huffingtonpost.com/social/draffi"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/draffi">draffi</a>:<br />

• Uranium City, Saskatchewan

  <a href="http://www.huffingtonpost.com/social/idyl"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/idyl">idyl</a>:<br />An abandoned mining town with some 5,000 souls in its heyday (1982).

• Rhyolite, Nevada

  <a href="http://www.huffingtonpost.com/social/kraig"><img style="float:left;padding-right:6px !important;" src="http://i.huffpost.com/profiles/34298-tiny.png?20090908232346" /></a><a href="http://www.huffingtonpost.com/social/kraig">kraig</a>:<br />Rhyolite is a ghost town in Nye County, in the U.S. state of Nevada. It is located in the Bullfrog Hills, about 120 miles (190 km) northwest of Las Vegas, near the eastern edge of Death Valley.

• Rhyolite, Nevada

  <a href="http://www.huffingtonpost.com/social/kraig"><img style="float:left;padding-right:6px !important;" src="http://i.huffpost.com/profiles/34298-tiny.png?20090908232346" /></a><a href="http://www.huffingtonpost.com/social/kraig">kraig</a>:<br />Rhyolite is a ghost town in Nye County, in the U.S. state of Nevada. It is located in the Bullfrog Hills, about 120 miles (190 km) northwest of Las Vegas, near the eastern edge of Death Valley.

• Elizabethtown, New Mexico

  <a href="http://www.huffingtonpost.com/social/Nina_Anthony"><img style="float:left;padding-right:6px !important;" src="http://graph.facebook.com/1301880638/picture?type=square" /></a><a href="http://www.huffingtonpost.com/social/Nina_Anthony">Nina Anthony</a>:<br />Old truck pointing the way to Elizabethtown, New Mexico, a once-bustling gold mining town boasting a population of 7,000, which was frequently visited by the outlaw Blackjack Ketchum.

• Two Guns, AZ. USA

  <a href="http://www.huffingtonpost.com/social/Chris_Shelton"><img style="float:left;padding-right:6px !important;" src="http://graph.facebook.com/27701151/picture?type=square" /></a><a href="http://www.huffingtonpost.com/social/Chris_Shelton">Chris Shelton</a>:<br />Two Guns AZ is a ghost town with a few remaining buildings. Including one with a skatable pool!

• Elkhorn Montana

  <a href="http://www.huffingtonpost.com/social/galloppinggeezer"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/galloppinggeezer">galloppinggeezer</a>:<br />Elkhorn Montana

• Oven inside the Meade Hotel Bannack MT

  <a href="http://www.huffingtonpost.com/social/galloppinggeezer"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/galloppinggeezer">galloppinggeezer</a>:<br />Oven inside the Meade Hotel Bannack MT

• Barber Chair Skinner's Bar Bannack MT

  <a href="http://www.huffingtonpost.com/social/galloppinggeezer"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/galloppinggeezer">galloppinggeezer</a>:<br />Barber Chair Skinner's Bar Bannack MT

• Dance & Stuart Virginia City MT

  <a href="http://www.huffingtonpost.com/social/galloppinggeezer"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/galloppinggeezer">galloppinggeezer</a>:<br />Dance & Stuart Virginia City MT

• Ha Ha Tonka Castle, Central Missouri

  <a href="http://www.huffingtonpost.com/social/Pixeltaker"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/Pixeltaker">Pixeltaker</a>:<br />Burned in 1942 along with the castle. Ha Ha Tonka was the name of a near-by lake. The 5,000 acres was originally purchased in 1903 by Robert M. Snyder, a wealthy business man from Kansas City. He planned to use it as a retreat from the rigors of the business life. In 1905 he was tragically killed in one of Missouri's first automobile accidents. His sons completed the castle. More tragedy struck between 1905 and 1942.

• Copper Queen Hotel's Cigar Man ( Who we thought was there )

  <a href="http://www.huffingtonpost.com/social/DinoChloe"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/DinoChloe">DinoChloe</a>:<br />Here in picture my family was on another ghost adventure to Bisbee,Arizona here there are many spirts here but this orb we belive was a man cause my mom saw a man .We Visthere before and the town is very historic it self.In this I forgot to add that this a orb a orb is a spirts engry ussually you see them in pictures or nightvision goggles or even with your own eyes !

• Encino, New Mexico

  <a href="http://www.huffingtonpost.com/social/Alex_Matzke"><img style="float:left;padding-right:6px !important;" src="http://images.huffingtonpost.com/google_profile_img/2292985.png" /></a><a href="http://www.huffingtonpost.com/social/Alex_Matzke">Alex Matzke</a>:<br />An abandoned house in Encino, New Mexico.

• Garnet Ghost Town

  Garnet, Montana

• Uranium City, Saskatchewan 2011

  <a href="http://www.huffingtonpost.com/social/ian_brewster_photography"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/ian_brewster_photography">ian brewster photography</a>:<br />Uranium City, August 2011 - thirty years after the mines closed

• Uranium City, Saskatchewan 2011

  <a href="http://www.huffingtonpost.com/social/ian_brewster_photography"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/ian_brewster_photography">ian brewster photography</a>:<br />Uranium City, 30 years after mines closed

• Medicine Mound, Texas

  <a href="http://www.huffingtonpost.com/social/Robin_Cole_Jett"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/Robin_Cole_Jett">Robin Cole Jett</a>:<br />Named after the four hills that served as places for Comanche vision quests.

• The George Walker House, Paradise, Arizona

  <a href="http://www.huffingtonpost.com/social/Winston_L"><img style="float:left;padding-right:6px !important;" src="http://s.huffpost.com/images/profile/user_placeholder.gif" /></a><a href="http://www.huffingtonpost.com/social/Winston_L">Winston L</a>:<br />George Walker founded the town of Paraddise. This is his 1902(06) home. http://www.thegeorgewalkerhouse.com

• Nevadaville, Colorado

  <a href="http://www.huffingtonpost.com/social/Phillip_Barber"><img style="float:left;padding-right:6px !important;" src="http://graph.facebook.com/1413395040/picture?type=square" /></a><a href="http://www.huffingtonpost.com/social/Phillip_Barber">Phillip Barber</a>:<br />Old ghost town very close to Central City, CO