"This day will always be hard, but this place will always be strong," former Mayor Thomas Menino told an invitation-only audience of about 2,500 people at the Hynes Convention Center, not far from the finish line, where two pressure cooker bombs hidden in backpacks killed three people and injured more than 260 others a year ago.
Vice-President Joe Biden, who attended the ceremony, said the courage shown by survivors and those who lost loved ones is an inspiration for other Americans dealing with loss and tragedy.
"You have become the face of America's resolve," he said.
Biden also praised the 36,000 runners who plan to run the marathon next week, saying they will send a message to terrorists.
"America will never, ever, ever stand down," he said, to loud applause. He added, "We own the finish line."
In the evening, after the tributes were over and most people had left, a man behaving suspiciously near the finish line dropped a backpack containing a rice cooker, police said. The man, who walked barefoot in a street in pouring rain, was taken into custody and was being charged with possession of a hoax device and disturbing the peace, Police Superintendent Randall Halstead said.
The backpack was blown up by the bomb squad as a precaution as was a second unattended backpack found nearby, police said, and no injuries were reported. Halstead didn't release the identity of the man in custody and wouldn't say what was in the second backpack or who owned it.
In Washington, President Barack Obama observed the anniversary of last year's deadly marathon attack with a private moment of silence at the White House.
"Today, we recognize the incredible courage and leadership of so many Bostonians in the wake of unspeakable tragedy," Obama said in a statement. "And we offer our deepest gratitude to the courageous firefighters, police officers, medical professionals, runners and spectators who, in an instant, displayed the spirit Boston was built on — perseverance, freedom and love."
Obama said this year's race, scheduled for April 21, will "show the world the meaning of Boston Strong as a city chooses to run again."
Authorities say two ethnic Chechen brothers who lived in the former Soviet republic of Kyrgyzstan and the Dagestan region of Russia planned and orchestrated the marathon bombings on April 15, 2013.
Tamerlan Tsarnaev, 26, died following a shootout with police days after the bombings. Dzhokhar Tsarnaev, 20, has pleaded not guilty to federal charges and is awaiting a trial in which he faces a possible death sentence. Prosecutors say the brothers also killed MIT police Officer Sean Collier days after the bombings in an attempt to steal his gun.
Prosecutors have said Dzhokhar Tsarnaev left a hand-scrawled confession condemning U.S. actions in Muslim countries on the inside wall of a boat in which he was found hiding following the police shootout.
At the tribute, several survivors of the bombing alluded to their injuries but focused on the strength they've drawn from fellow survivors, first responders, doctors, nurses and strangers who have offered them support.
"We should never have met this way, but we are so grateful for each other," said Patrick Downes, a newlywed who was injured along with his wife. Each lost a left leg below the knee in the bombings.
Downes described Boston Strong, the slogan coined after the attack, as a movement that symbolizes the city's determination to recover. He called the people who died "our guardian angels."
"We will carry them in our hearts," he said.
Downes said the city on April 21 will "show the world what Boston represents." He added, "For our guardian angels, let them hear us roar."
Adrianne Haslet-Davis, a ballroom dancer who lost her left leg below the knee and has recently returned to performing on a prosthetic leg, said she's learned over the last year that no milestone is too small to celebrate, including walking into a non-handicapped bathroom stall for the first time and "doing a happy dance."
Gov. Deval Patrick spoke of how the attack has drawn people closer.
"There are no strangers here," he repeated throughout his speech.
Carlos Arredondo, the cowboy hat-wearing spectator who was hailed as a hero for helping the wounded after the bombings, said he went to the tribute ceremony to support survivors and their families.
"You can see how the whole community gathered together to support them and remember," Arredondo said.
After the tributes, many of those in attendance walked in the rain to the finish line for a moment of silence that coincided with the time when the bombs went off. Bells rang, and a flag was raised by transit agency police Officer Richard Donohue, who was badly injured during a shootout with the bombing suspects.
Earlier in the day, a wreath-laying ceremony drew the families of the three people killed last year — Martin Richard, Krystle Campbell and Lu Lingzi — and Collier's relatives.
Associated Press writer Philip Marcelo contributed to this report.