An abstract monument to a symphonic composer.

This irregularly shaped sea fortress has defended not one but three different sovereign states.

A subterranean house of worship carved right out of the bedrock.

A fascinating insight into daily life in the Eastern Bloc.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

This police call box harkens back to an era of pre-radio communications, and has a rather unique feature.

In England, an 18th-century water-powered workshop still stands.

One of the last remnants of the Bessemer process that revolutionized steel production during the industrial age.

The whimsical steel spider lurking in the shadows of this suspension bridge shows that engineers can have a sense of humor.

Cemetery established by the Victorians as a solution to the overflowing graveyards.

An enormous steel waterfall is a nod to the substance that shaped Britain's Steel City.

Amidst towering office buildings, a local pub lives inside Sheffield’s oldest surviving domestic building.

A tribute to the women who quietly kept the local steelworks alive during both world wars.

One of the last doorless, continuously moving elevators still in use in the U.K.

Long-secret natural history museum, featuring the skull of a "Terror Bird."

The view from this giant Stone Age toad is unexpectedly beautiful.

The greatest real estate coup of all time.

Fortune tellers, snake charmers, poets, and storytellers all gather on this historic square in Morocco.

Traditional 11th-century outdoor tannery.

Thousands of narrow alleyways in an ancient medieval city make up what's believed to be the world's largest car-free urban zone.

World's largest film studio, where visitors tour the decaying sets that litter the harsh desert environment.

The other side is actually green.

Founded as a refugee camp, now a popular tourist spot.

The patches of trees pay tribute to Queen Elizabeth II.