What was once the largest NFL stadium.

Over a thousand feet beneath the Detroit streets is a subterranean metropolis few are allowed to enter.

Where the Model T was made and the assembly line was invented.

The Beaux-Arts aquarium boasts a vast collection of saltwater and freshwater fish on an island in the Detroit River.

These enduring murals depicting a distinctly Marxist tribute to capitalism could not even be defeated by McCarthyism.

This Delaware River bridge is emblazoned with a catty slogan from a more prosperous time.

One of New Jersey's oldest surviving buildings still bears the mark of our former British overlords.

Home to the largest urban bat colony in North America, estimated at 1.5 million bats.

Twenty churches beautifully painted by 19th-century Czech and German immigrants in Texas.

Allowing humans and fish alike to migrate from freshwater to saltwater and back again.

This former coal gasification plant found a curious second life as a popular public park.

A favorite with sightseers and locals alike, this Norwegian funicular provides easy access to a stunning view of Bergen and its environs.

The burning of this 12th-century church kicked off a campaign of Norwegian Black Metal terror.

This "preacher's pulpit" once used for pagan ritual, is home to a new, and dangerous ritual.

Monuments don't get much more metal than these three giant viking swords planted in a Nordic hill.

Norway's oldest cathedral still in use.

Oslo's historic toboggan run has been letting thrill seekers slide from train stop to train stop for over a century.

Home to three historic ships from the age of Vikings.

One man's exploration of the human form, including the bizarre and delightful "Man Attacked by Babies."

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

A geological mystery on Camelback Mountain.

A downtown park built on top of unclaimed graves.

The Denver airport is guarded by a 32-foot-tall sculpture of a demonic horse.

This underfoot portrait is the work of a disgruntled painter inspired by a tragic poem.