While not Turkey's deepest underground city, this subterranean redoubt is the largest.

Ancient serpentine sacrifice holder that has stood the test of time.

A marvel of Byzantine engineering under the streets of Istanbul.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

The mummified right fist of a 1,000-year-old saint-king sits inside an ornate golden reliquary.

A statue in Budapest's Liberty Square honors the former U.S. president's efforts to end the Cold War.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

London's last remaining public soapbox site has seen speeches from Karl Marx, Vladmir Lenin, and George Orwell.

The anatomical-pathological collection of a man who changed surgery.

Giant, friendly pelicans in Central London, the most unlikely of places.

The perfectly preserved underground rooms where Churchill plotted the war against Germany.

One of the Seven Wonders of the Modern World holds the world's tallest metal staircase.

This seemingly cursed monument is dedicated to one of Canada's great war heroes.

The seat of Buffalo government is a gorgeous Art Deco palace.

This Niagara Falls tourist trap is a world bright with neon and curiosities that will inspire love, hate, or a mixture of both.

Created by four famous men, the beautifully designed Buffalo State Asylum was resurrected as a hotel and art center, but still boasts a ghost story or two.

One of many reminders of Tesla's scientific contributions overlooks the falls which inspired him.

Toxic waste disaster that founded the Superfund program.

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

The longest escalator in the Western Hemisphere takes over three minutes to ride down.

The tallest The Church of Jesus Christ of Latter-day Saints temple in the world soars above the Beltway.

A girls' boarding school inspired by the Chicago World's Fair, once abandoned, now restored to strange and scenic glory.

An astounding collection of medical specimens, including bits of President Lincoln.