张家界天门山，中国 Tianmen Mountain in Zhangjiajie, China (© Bogdan Dyiakonovych/Shutterstock)

张家界天门山，中国 Tianmen Mountain in Zhangjiajie, China (© Bogdan Dyiakonovych/Shutterstock)

Take the stairs

If you want to celebrate Take the Stairs Day in style, look no further than China's Tianmen Mountain (literally Heaven's Door). About 5,000 feet above sea level, the hole in the mountain is the highest naturally formed arch in the world. Originally a cave, it became an arch in 263 AD when the backside of the mountain collapsed, creating the dramatic opening we see today. You'll have to climb 999 steps to make it to the top, but we promise the view is worth it.