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

The Denny Substation has been called "the coolest substation in the world" and sits in a densely populated Seattle neighborhood.

In this subterranean brick arcade, a small shop continues the ancient practice of bookbinding.

Five varieties of trees with custom-designed grates around the trunk are planted along the route of the Seattle Transit Tunnel.

The tech giant built three enormous glass orbs in Seattle so employees could work inside a rainforest greenhouse.

A rotting tree in the middle of Seattle doubles as an elaborately-controlled art piece.

Dedicated to the history of the health sciences.

Charleston's historic city jail once held everyone from pirates to Civil War POWs.

Paths are maintained, but trees have taken over plots.

Once the most flame resistant building in the country, the South Carolina Historical Society building was almost burnt down in a fire.

South Carolina's last remaining slavery auction house is now a museum devoted to its own tragic history.

Built in 1931, this small passageway is believed to be the first modern skyway.

This double-arched masonry highway bridge is the only structure of its kind in Minnesota.

Triangular House built on a leafy residential street in St. Paul.

The basement bowling alley of this St. Paul dive bar is decorated with thousands of dollar bills.

The Real LegoLand.

A giant donut stands as a popular symbol of Los Angeles iconography.

The sun acts as a key that only fits this giant keyhole twice a year.

Practice your Dirty Dancing lifts in the manmade lake where Johnny Castle himself did.

This ordinary set of steps is a must-see destination for fans of a certain romantic anime.

Once a black market electronics marketplace, now an otaku shopper's paradise.

A Buddhist temple to honor insects that died for science.

Shrine to Japanese water-goblins, complete with their preserved body parts.

An oddly touching memorial to a little-remembered nuclear tragedy.