The fifth-longest natural arch in the world, and the longest outside China.

A striking lighthouse with views of the Gulf of Mexico and of a military air show.

The spot where three Protestant clergymen were burned at the stake during the reign of "Bloody Mary."

Carved initials which are nearly 500 years old preserve the deposed Queen's presence at Hampton Court Palace.

A theatre built to house the rowdy Oxford graduation ceremonies became the stage for a debate about God's existence.

Ancient human remains unearthed around the iconic monument.

The "lost friend” is the most famous of the six moai statues that were removed from Easter Island.

England's oldest surviving hedge maze has been confusing visitors for over 300 years.

Famously misunderstood wonder of the ancient world

A charming 17th-century alley is lined with secondhand bookstores and antiquarian shops.

One of corporate America's best-kept secrets is also one of the most publicly displayed.

The enormous 250-room Vanderbilt mansion conceals hidden doors and secret passageways.

The world's tallest statue of an American hero.

An unrealized Taoist palace left abandoned in a Houston suburb.

The prototype for all Nazi concentration camps.

Daily jousts and dancing barrel makers in Munich's mechanical clock.

The fairy tale castle of the "fairy-tale king."

One of the three perfect vellum copies of this historic book known to exist is on display in a specially-designed case.

One critic described it as "middle Mussolini, early Ramses, and late Neiman-Marcus." Another called it an architectural "natural disaster."

The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

An overlooked memorial honoring the local Washington residents who died in World War I.

The little-known, 300-year history of the area includes former lives as a bustling tobacco port, parking lot, and industrial dump.

Members of Congress have traveled between the buildings on Capitol Hill for a century hidden from tourists, press, and storm clouds.

A little marble compass above George Washington's (empty) tomb in the Capitol marks where D.C.'s four quadrants intersect.