New York City's only preserved family home from the 19th century.

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

The remains of what was, not so long ago, the world's largest city.

One of only two commuter aerial tramways in the United States.

The world's second-largest sundial, made entirely out of stone.

The prototype for all Nazi concentration camps.

The second-longest continuous wall on the planet protects a hidden secret in the deserts of India.

Mysterious 500-year-old tapestries depict a unicorn hunt.

A celebration of capitalism in Midtown.

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

The only swimming pool listed on the National Register of Historic Places is emptied and refilled each day with naturally filtered water.

Behind a bodega is a small museum of relics and ephemera showcasing the history of New York.

Two thousand artifacts from around the world collected by one woman who loved to travel.

A tiny piece of the Moon is embedded in this stained glass masterpiece.

Trick water gardens from 1619 featuring a 200 piece mechanical theater powered by water.

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

Read between the lines of the subway map to find the hidden abandoned Civil War fort.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

Ride the subways of yesteryear.

A fantastic castle rumored to be the birthplace of King Arthur.

Bizarre lunar-like landscape with thousands of large stone "hoodoos."

Elevated freight railway turned wildly successful urban park.

The celebrated eyesore created by starry-eyed sweethearts.

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.