A sacred site for Native Americans surveyed by George Washington and owned by both King George III and Thomas Jefferson.

A secretive collection featuring objects that were designed specifically for U.S. intelligence operations.

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

A dramatic, 360-degree recreation of Pickett's Charge in the Civil War.

The prototype for all Nazi concentration camps.

Soaring over 6,000 feet in the Bavarian Alps, this beer garden was once Hitler's 50th birthday present.

Originally envisioned by King Ludwig II to rival Versailles, Herrenchiemsee's "New Palace" remains half-gilded for lack of funds.

A small but immensely extravagant palace built by the "Night King."

The fairy tale castle of the “fairy-tale king,” this was also the inspiration for Disney’s “Sleeping Beauty.”

Sitting in the basement of a castle, the largest wine barrel in the world is bigger than most apartments.

World's largest barrel containing an inn.

The birthplace of an eccentric alchemist and possible inspiration for the fictional reanimator of monsters.

Artifacts and memories from the Vietnam war, located in a place that experienced it first hand.

Site of the largest volcanic eruption in the last 25 million years, one which may have nearly wiped out humanity altogether.

Holy Hindu shrine in an enormous, monkey-filled limestone cavern.

What is the Thing?

The semi-reclaimed ruins of this canal were once part of an ambitious plan to reroute the mighty potomac.

Collecting 700 years of mechanical death-dealing, the NRA's sprawling gun museum is a revealing testament to the American obsession with armament.

Frank Lloyd Wright’s most iconic home dangles over a Pennsylvania waterfall.

A priceless collection of the Nation's cryptologic history.

Outsider art meets paleontology at this roadside reptile repository.