Dating back almost 400 years, the oldest public collection library in the United Kingdom was once the study hall of Karl Marx.

Peace Park and the Atomic Bomb Dome.

Stepping away from the glitz of mobsters and casinos to learn about the other history of Vegas.

This ominous Albanian fortress houses tanks and downed planes as a reminder of their victories over Western imperialism.

The remains of this ancient fortress atop a manmade hill look as though they were built into a volcano.

Strange red rock formations that have been attributed to a higher power for hundreds of years.

This tunnel entrance is built to resemble a grand castle but no one is quite sure why.

Despite repeated attempts to make it work, this former mining town is now nothing but dust and memories.

This historic steamboat is scuttled just a few hundred feet from where it was built over a hundred years ago.

The centuries-old trees lining both sides of this dirt road may become Madagascar's first natural monument.

The sound of swaying stalks in this stunning grove has been named a governmentally recognized sound.

This historical Netherlands fortress still bears the marks of its single siege.

One of the oldest and certainly best preserved Cistercian abbeys still in existence.

This huge metal monument is slowly being stripped to its concrete skeleton.

Gutted during the Liverpool Blitz, this architectural husk has been left destroyed in honor of the dead.

On the Oregon coast there is a natural hole that seems to be draining the sea.

Despite a fraught and controversial history this African island holds a powerful monument to the tragedy of the slave trade.

This subterranean necropolis holds three floors of antler-dug grave caves.

The remains of a failed attempt at medieval nerdery are hidden deep in the woods of Virginia.

This small city where almost everyone lives in the same building can only be reached via North America's longest tunnel.

Submerged trees jut ghost-like out of an idyllic turquoise mountain lake.

A community-run museum invites visitors to explore Jewish communities before and after the Holocaust.

What can compare to the comforting sound of 10,000 toilets running?

A site where “the ravages of the war are more striking…than any other place in contemporary Spain.”