The New York Times' health blog, "Ask Well," makes an interesting health comparison between walking and climbing stairs. Veteran health writer Gretchen Reynolds writes that slowly taking stairs will burn almost twice the energy than walking at an everyday pace along a flat surface.
Stairway walking also "activates more muscles," might have balance benefits, and increases cardiovascular fitness more quickly than regular walking on a level surface. Even walking down stairs seems to use up more energy than flat walking!
A really healthy way to have fun outside! (Howe stairs, Capitol Hill)