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

The "lovely red Vega" of the legendary record-settling pilot.

The first American department store, and home to the largest operating musical instrument in the world.

A former major munitions plant that has been converted into a sprawling art space.

This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.

Erotic art covers the walls of the largest ancient pleasure palace.

An idyllic swimming pool tells the tale of Hemingway's trouble with women.

The most confusing clock in New York.

The former home of the Nobel Prize-winning American writer is now home to dozens of six-toed cats.

Every equinox this Maya pyramid puts on a spooky ancient light show.

Giant acorn-shaped 19th century gazebo from which suburban Washingtonians gazed upon the original "silver" spring.

A curious fountain that has no water and includes Satan, a crab, and 9 giraffes.

These mysterious ancient stone spheres were created by a civilization lost to time and are now mostly lawn ornaments.

Oldest Protestant church in the Middle East, designed to resemble a synagogue.

A "miracle" that seems to produce more holy fistfights than holy revelations.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

The last moments of the ill-fated Pompeiians, frozen forever in plaster.

Ancient snack bar of the Roman Empire re-opened.

Once home to seven different roller coasters, Glen Echo has undergone many transformations since its founding in 1891.

An astounding collection of medical specimens, including bits of President Lincoln.

The sci-fi villain is a little-known inhabitant of the U.S. capital's largest cathedral.

Commemorating the spot where the famous scientist fed his pigeons.

Go inside to really appreciate this 500-year-old technological masterpiece.

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