This pre-Revolutionary War grist mill ground corn and flour for soldiers in seven American wars.

The world's most remote permanent settlement on an active volcano.

Eccentric concrete mansion and museum designed and built by hand from the inside out.

The internal railway of one of the biggest steel plants in America has been transformed into a linear park with unique industrial views.

A park full of outsider art, created by college students studying outsider art.

Mysterious library of an infamous financier and spiritual seeker.

Vikings and Evangelicals have both had a hand in this replica medieval church.

Behold the rickety wooden glory of the world's oldest operating roller coaster.

Over a dozen Native American earth mounds dating back over 2,000 years dot this Tennessee archaeological park.

A favorite of Amelia Earhart, ranking among those rare bridges that can be crossed without changing sides of the river.

A museum dedicated to exhibiting remarkable outsider art.

This simple convenience store sits on the location where the Ouija board was named—and has a plaque to prove it.

This strange seaside tower got its name from a wealthy eccentric who would hide coins among its stones.

Nine of the very few concrete ships ever made in the U.S. are beautifully decaying off a Virginia pier.

These World War I shooting range tunnels are now haunted halls of underground graffiti accessed through the roots of a tree.

This magnificent Cincinnati graveyard is also a popular public park.

The fifth-longest suspension bridge the world, connecting one Michigan peninsula to another.

This shallow cave got its name from copious amount of human bones found inside.

Island where motor vehicles are banned -- home to the only carless highway in the United States.

Once the "Eighth Wonder of the World," this iron railroad bridge was decimated by a tornado.

To avoid the demolition costs this abandoned drawbridge was simply left in the up position.

This natural sea cave hides a small wonderland of natural turquoise beauty.

An 18th-century Catholic church converted into an eccentric temple of music and bacchanalia.

It's not hard to see why the historic Peabody Conservatory of Music's library has been described as a "cathedral of books."