Light still pours into the ruins of this ancient Islamic observatory.

The Avenue of Mausolea is a series of grand palatial tombs.

This "tower of death" has acted as an observatory, a religious hub, and an executioner's lair.

Yemen's "Stone Palace" looks like it was carved right out of the tall stone column on which it is built.

2300-year-old Roman road connecting the empire.

This ritzy Italian market is built around a statue of an unforgiven heretic who was burned for his belief in an endless universe.

A volcanic old faithful, Stromboli has been erupting continuously for the last 2000 years.

Mortarless walls that stretch for miles are a lovely solution for creating grazing land in the harsh terrain of the Aran Islands.

A hugely vast Irish landscape of barren rock that stretches for miles.

This neon blue river gets its color from a unique mix of bacteria and volcano minerals.

This imposing memorial contains the remains of Che Guevara — and 29 other guerrillas who died with him in Bolivia.

On this tiny spot of land in the middle of Lake Titicaca the only ones who do the knitting are the men.

The Uros people live on floating reed islands in lake Titicaca.

The stones of this Incan wall complex fit together so well you couldn't fit a piece of paper between some of them.

Preserved Inca city and site of the last Inca stronghold against the Spanish conquistadors.

If you’ve ever seen a picture of Machu Picchu, then you’ve seen a picture of Huayna Picchu—you just didn’t realize it.

The mysterious "Candelabra of the Andes" could represent anything from a god's trident to a hallucinogenic plant.

Human ancestor’s 3.6 million year-old footprints.

The centuries-old trees lining both sides of this dirt road may become Madagascar's first natural monument.

The central mosque of this Mali town is entirely built from mud.

These homes carved into the mountains seem to defy the laws of nature.

Ancient Manuscripts showcase the civilization of West Africans during the Middle Ages.

These Australian rock formations look like Martian beehives that have grown up out of the landscape.

This trio of Australian rock spires may have inspired aboriginal legend or just modern tourism.