An institution dedicated to the towering buildings that make up skylines in New York City and around the world.

The location where the iconic movie character declared it was time to go home.

The first permanent memorial to a unique secret weapon of World War II.

The massive, incredibly rare instrument is over 11 feet tall with a range so deep it goes lower than humans can hear.

A geological mystery on Camelback Mountain.

A unique collection of military history dating back to the American Revolution.

Museum celebrating the history of computers, especially their role in codebreaking.

Home to Alan Turing, the cracking of the Enigma code, and Captain Ridley's shooting party.

This stone honors the U.S. Rangers who made Carrickfergus their home base during World War II.

A boulder in the Churchyard of Down Cathedral marks the legendary burial place of "The Apostle of Ireland."

The ship built to ferry passengers and goods to the doomed Titanic is now the last remaining White Star Line vessel.

Northern Ireland's Brobdingnagian stepping stones.

John Hendrix predicted the creation of the "Secret City" built as part of the Manhattan Project.

One of the Cemestos prefab homes built to secretly house thousands of Manhattan Project workers.

The grave of America's 11th president is not in some grand monument but instead it's hidden away on the grounds of the Tennessee Capital.

An abandoned town is hidden in Great Smoky Mountains National Park.

The hotel where Martin Luther King Jr. was shot is now a museum dedicated to his work.

The secret city built by the Manhattan Project.

Tour the dark and beloved poet's former cobwebbed basement, which may have inspired "The Black Cat."

America's smallest national park site is the former residence of exiled Polish national hero Thaddeus Kosciuszko.

World's first "penitentiary," meant to be humane, drove men insane.

Hiding in plane sight.

The Hveragerði fissure runs through this unassuming shopping center.

A Cold War atomic camp buried under the ice is now emerging because of global warming.