This nine-story building can be played like an instrument.

These strange large stones served as a campsite and lookout post for generations of Native Americans.

This communist behemoth is the heaviest building in the world and a legacy of a brutal regime.

This bazaar is one of the oldest in the Arabian world.

This spectacular mosque houses the second-largest chandelier in the world.

The world's largest frame offers spectacular views of the city's past and present.

In Kazakhstan, a colorful cathedral with many lives once survived the most powerful earthquake in the region.

A museum dedicated to the history and exploration of both popular music and science fiction.

This small 16th-century church in Athens is almost entirely surrounded by a modern building.

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

New Zealand's only running funicular railway.

A galaxy of glowworms—larvae of a gnat—hides deep in the belly of these caves.

Home to items never before seen by the public.

A bust of Franz Kafka spins in pieces, reflecting the writer's inner torment.

A mocking tribute to the past and modern leadership of Prague.

Despite attempts by local police to discourage it, Beatles-inspired graffiti has been a means for artists to air grievances for decades.

This Prague museum collects brutalist relics and memories from the country's former Soviet rule.

The only recreation of William Shakespeare's indoor playhouse.

The ornate miniature mansions were built for Istanbul's feathered residents.

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

Once at the center of U.S. finance, the historic Trading Room was meticulously recreated piece by piece and rebuilt in the Art Institute.

This ceremonial mound is one of the first officially recognized Native American historical sites in North Carolina.

Formerly the most gerrymandered district in the U.S., it twisted and turned along racial borders.

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.