This seaside sanctuary was once one of the most important religious sites for women in ancient Greece.

Also known as the Temple of Poseidon, this is one of the best-preserved Greek temples in the world.

The remains of this medieval Roman road and lookout towers dot the rugged coastline of southern Lazio.

A medieval stronghold rising over the ruins of ancient Roman villas along Rome's southern coast.

An old watchtower from the 16th-century now watches over sulfur springs and one of Lazio's last coastal woodlands.

A Nesting Doll of Churches.

This ancient market is often referred to as the oldest shopping mall in the world.

Ancient ruins hidden underneath a modern luxury hotel.

This Alaskan town appoints the general store's resident feline as honorary mayor.

Considered by many to be one of the most dangerous highways in Alaska.

The now-serene site of the largest earthquake ever recorded in North America.

Running under an entire mountain, the longest highway tunnel in North America is kept fresh using portal fans and jet fans.

This small city where almost everyone lives in the same building can only be reached via North America's longest tunnel.

This WWII-era military installation once held an entire city within its walls - now, its walls are falling down.