Allowing humans and fish alike to migrate from freshwater to saltwater and back again.

A giant Troll lurks under one of Seattle's oldest bridges.

A museum dedicated to the history and exploration of both popular music and science fiction.

A walk through the historic city center, under the streets of Seattle.

This country market harbors goats on its roof.

An elaborate shrine dedicated to the four corners of the world unfortunately misses its mark.

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

Huge stone depressions which may have acted as an Incan agricultural experiment.

The intricate stonework of Machu Picchu serves as a testament to Incan engineers.

Human ancestor’s 3.6 million year-old footprints.

The curious underground history of keeping Paris clean.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

Natural history museum celebrating biodiversity with a parade of taxidermy animals.

A haunting collection of the vanished and disappearing natural world.

This massive subterranean fissure is known as the "underground Grand Canyon."

This one-time health resort was used by aristocrats around the world.

A fountain standing as a testament to a doomed alliance.

The ancient latrines of the Greeks, in all their public glory.

Roman ruins top white travertine terraces formed by ancient hot springs.

A marvel of Byzantine engineering under the streets of Istanbul.

Ancient serpentine sacrifice holder that has stood the test of time.

A minotaur, a labyrinth, and a dubious restoration pull in visitors from around the world.

This famous archeological mystery may be an ancient example of movable type.

This famous city eluded concrete detection until the early 2000's.