The collection is housed in an exquisite mansion that makes you feel like you've been transported to an Italian villa.

This ostentatious Italianate palace of an Oklahoma billionaire is filled with several themed mini-museums.

Travel through the hidden underbelly of the city in colorful tunnels filled with art and history exhibits.

An immersive art experience built by local arts collaborative, Factory Obscura, in the building formerly known as The Womb, a psychedelic arts center founded by the frontman of the Flaming Lips.

It reportedly took three years to sort through all the objects in this eclectic lifelong collection.

One of the best examples of Art Deco architecture in the United States.

One of the largest Masonic temples in the world, created at the height of the oil boom in ostentatious style.

Tucked away in the Tower of London is the weapon once used to execute high-profile prisoners.

This amazing ancient cave was kept secret for seven years to protect it from the public.

Dedicated to preserving the history of free Black communities in Brooklyn and beyond.

The only diamond mine in the world where you can keep what you find.

There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

This ancient tomb in the West Bank is a holy site for Jews, Muslims, and Christians alike.

This dome-shaped mountain boasts amazing views and has a rich religious history.

The only quarter of the Old City not dedicated to a major world religion.

The maze-like transportation hub contains abandoned areas, derelict stores, and a resident bat colony.

Hidden beneath a washing machine in a fake kibbutz, this secret bullet factory has been preserved as a museum.

This "Jewish Sistine Chapel" was designed to reinvigorate Judaism's artistic legacy but was almost lost to misguided restoration.

A sprawling ancient Jewish cemetery with over 30 rock-hewn burial caves.

Squeezing inside this deep, narrow canyon reveals a festival of desert colors.

Sitting right on the border between East and West Jerusalem this modern art museum is in itself a symbol of Israel's hoped-for unity.

Descend 2,030 years into the past in an ancient tunnel built to support Jerusalem's most famous wall.

Brightly colored 30-foot-tall totems light up the desert sky just outside Las Vegas.

Detailed facade of a brownstone in Boerum Hill.