Bombed and burned, this monument represents the often controversial ties between Vietnam and Cambodia.

Khmer Rouge's high security prison.

A quick and simple solution to Cambodia's train woes.

This impressive clifftop temple was once at the center of an international custody dispute.

This Cambodian riverbed is covered in ancient Hindu carvings both above and below the waters.

5,000 skulls in memorial to those killed by the Khmer Rouge.

A battle between nature and architecture in the Cambodian jungle.

Thousands of narrow alleyways in an ancient medieval city make up what's believed to be the world's largest car-free urban zone.

The other side is actually green.

One of its engravings is believed to be among the first representations of medical and surgical instruments.

The largest known Ancient Egyptian obelisk.

These Egyptian statues have survived for 3,400 years and were an acoustic wonder of the ancient world.

Every hour the doors open to reenact the legend of the heroic mayor who saved his town by drinking a gallon of wine.

It's good luck to be mocked by this monkey.

The "Prussian Versailles" that is as glorious today as when it was built.

Once the tallest building in the world, this abandoned church is now a monument to the destruction of WWII.

The great Danube river starts here.

The prototype for all Nazi concentration camps.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

The most visited, and possibly most controversial, museum in Germany.

A small but industrious mining operation that allows visitors to touch precious gems while they are still in the rock.

A series of waterfalls so massive they straddle the border of Argentina and Brazil.

Morocco's largest Jewish cemetery.

This opulent 16th-century Maharaja’s palace is a unique mix of Hindu and Muslim designs.