At the foot of the stairs on the north face of El Castillo, in the Maya ruins of Chichén Itzá, Mexico:

Should you make it to Chichén Itzá, just remember — you can walk right up to the steps, but don’t even think about climbing them. Not that many years ago (until 2006), you could climb these to check out the temple at the top (and take in a fantastic view). But sadly, somebody slipped and fell down the stairs (to their death) — the structure’s been off-limits ever since.