This 14th century castle withstood years of battle but is now sliding off the hills into the Danube.

A submerged village appears when dam levels drop.

An ancient city exhumed from the depths of the ocean.

This protected area in Lake Huron contains some of the world’s best-preserved shipwrecks.

Bioluminescent firefly squid light up this Japanese fishing port.

One of the world's few mounted blue whales, its jaws are hinged open allowing visitors to descend into a lounge.

The world's largest aggregation of great white sharks is at a mysterious spot in the middle of the ocean.

An homage to the medieval rulers of Bulgaria.

Creek water that starts here has a 50/50 chance of ending up in the Atlantic or the Pacific.

Soldiers were buried next to Lee's house in the center of Arlington Cemetery to dissuade the general from reclaiming his property after the war.

Once an indicator of social class, the color blue has come to define this city on the edge of the Thar Desert.

"Unity, Creativity, Beauty."

The only land territory disputed between the U.S. and Canada.

A striking symbol of the Bulgarian capital.

This San Diego museum is dedicated to preserving women’s historic achievements.

Hundreds of mossy stones engraved with bits of philosophy, literature and random musings.

A well-preserved medieval village nested on a rocky outcrop and surrounded by a network of cliffs, natural bridges and canyons.

An enormous warehouse filled with parade floats collected from over 50 years of patriotic celebrations.

New York's oldest and possibly grandest keeper of books.

A memorial to the unknown and unheralded men and women of the Cold War military and intelligence services.

The 1936 Summer Olympics site is a crumbling remnant of sportsmanship and a history its host country would like to forget.

One of the most enjoyable bits of history at Coney Island and “the most romantic ride in the world.”

A son's promise to his dying father in the form of a covered bridge filled with thousands of seashells.

This water tower slanted at an uncomfortable angle off the old Route 66 was an ingenious marketing ploy.