A preserved portion of an ancient Athens barrier is displayed in a hotel basement.

A Byzantine-era church hidden in a wooded area below the Acropolis.

These caves secretly held national treasures during World War II.

A terrific purveyor of natural history objects and curios.

These historic buildings once housed the headquarters of one of the most infamous gangs of New York.

The artist and New York City icon lived, worked and died in this converted carriage house owned by another iconic artist, Andy Warhol.

A trove of century-old litho stones from the Puck Building's printing days were discovered behind a cellar wall, and are now hanging in the store.

This wall on a street corner in Lower Manhattan has been a blank canvas for a rotation of renowned artists since the 1980s.

No monkeying around, this fountain was really named after the classic sci-fi film.

The crown jewel of the Queens Museum is a nearly 10,000-square-foot architectural model of the city originally built for the 1964 World's Fair.

The remnants of two World's Fairs are here, complete with a 12-story globe, a mini-Manhattan, and a UFO-shaped pavilion.

Dive bar built out of the remains of a whaling ship.

The last example of an innovative piece of surveying equipment now stands in its inventor's hometown.

Each year these high desert hills are absolutely covered with poppy flowers in a surreal show of nature.

This former open-pit manganese mine is now a massive graffiti canvas.

Dyed by iron oxide over centuries, these sandstone rocks rise thousands of feet into the sky.

An old railroad grade built for the construction of Hoover Dam is now a recreational trail featuring several tunnels and sweeping views of Lake Mead.

A homage to the King at the hotel where he revived his career.

Experience a charming 1930's version of "infotainment."

A Norwegian-born sculptor created these soaring guardian angels at the entrance to Hoover Dam.

A giant open-air sculpture made of over 200 full-sized boats.

These banned cigarette vending machines now sell little pieces of pocket-sized art.

An exotic wildlife habitat right off The Strip.

An overlooked monument to the celebrity gangster who helped put the sin in Sin City.