the.com/stairs
gravity's stubborn enemy, climbed by everyone, conquered by no one without a little sweat
falling riskStairs send over a million people to ER yearly
penrose trickSome staircases loop forever, but only on paper
ancient designStone steps date back over 4,000 years
odd step ruleBuilders favor odd counts to ease your stride
fitness hackClimbing burns more calories per minute than jogging