If you want to celebrate Take the Stairs Day in
style, look no further than China's Tianmen
Mountain (literally Heaven's Door). About 1,500
metres 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.