A marvel of Byzantine engineering under the streets of Istanbul.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

The inky volcanic sand leads to reefs teeming with aquatic life waiting to be discovered by snorkelers and divers.

This Balinese sea temple is thought to be guarded by the hundreds of monkeys that live around it.

Sacred waters rescued from the wrath of a volcano.

Isolated atop this Balinese sea crag is a lovely Hindu temple that is said to be guarded by sea snakes.

The name of this ancient Indonesian temple translates as "Elephant Cave" but it could be more accurately called "The Hellmouth."

Hindu temple of the dead home to hundreds of long-tailed macaques.

Wall Street has a new heroine, a bronze statue of a small but fierce girl.

The home of the first American-born saint is one of the only curved buildings in New York.

This Wall Street bar was once a hub of revolutionary activity where Washington famously bid farewell to his troops.

Walk into the 19th century without leaving Brooklyn.

Amid the bustle and noise of the Financial District hides a secluded garden oasis above the city streets.

Lie in a hammock where George Washington stood.

Michael Jackson got Bad and Crocodile Dundee walked on heads in this iconic Brooklyn subway station.

Ride the subways of yesteryear.

In the middle of downtown Brooklyn lies a 165 year old secret hidden right below the surface (closed to the public indefinitely).

This innocent-looking townhome is actually a subway exit.