650 feet out of the flat ground of Guatape, Colombia

A massive stone rising over 650 feet out of the flat ground of Guatape, Colombia, the Piedra de Penol or El Peñon de Guatape was once worshiped by the Tahamies Indians. By the 1900s, the massive 10-million-ton rock was seen by local farmers as a nuisance, a giant version of the rocks that the farmers regularly dug out of their fields.

In 1954 a group of friends—supposedly at the urging of a local priest—climbed the rock using a series of boards wedged into a crack. These were the first people known to have climbed El Peñon de Guatape. (It is unknown whether the Tahamies had a way of ascending the stone.) Climbing the huge stone took five days, but the top of the rock revealed both beautiful views and a new species of plant, Pitcairma heterophila. The rock soon became a modest tourist attraction.

The rock, which is almost entirely smooth, has one long crack, the one that the climbers used in ascending it. In the crack was later wedged a 649-step masonry staircase, the only way to get to the top of the Piedra de Penol. In the 1970s, the area was dammed, and the view from the rock changed: It now overlooks a dramatic series of lakes and islands.

Today, you can ascend the rock (apparently owned by a local family, though also designated by Colombia as a "national monument") for 2 US dollars. There you'll find a few religious relics and a three-story lookout tower.