Nature lovers and fitness fanatics, it's time to lace up your sneakers and start hitting the stairs, because the World Wildlife Fund's CN Tower Climb for Nature returns this weekend for its 26th year.
On April 16 and 17, the CN Tower's inner stairwell will be open to individuals and teams looking to climb its 144 flights.
However, if you aren't ready to tackle the tower's stairs this weekend, the United Way also holds an annual stair climb in the fall — which gives you plenty of time to start training.
And even if you don't plan to climb the tower, you may want to consider climbing the stairs around you at work and at home. According to researchers from Concordia University, taking the stairs daily can keep your brain young and healthy.
In the slideshow below, we answer 25 questions about climbing the CN Tower, from how many steps you'll have to take to what happens once you reach the top.
Is climbing the CN Tower on your bucket list? Let us know in the comments below.
Also on HuffPost