America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

An unknown Hall of Fame in Jackson, Tennessee.

This funicular railway rumbles along for a mile up the nearly vertical face of Chattanooga’s Lookout Mountain.

The hotel where Martin Luther King Jr. was shot is now a museum dedicated to his work.

Walk the whole Mississippi River!

Enormous lake at the bottom of a unique cave system.

Visit this playground of waterfalls, caves and sinkholes.

You thought Santa Claus didn't exist, but it turns out you were wrong.

Ornate limestone building now filled with geologic specimens, and more.

The longest navigable underground river in the United States is home to countless blind and albino animals.

A medical facility that has been kept frozen in time.

A hidden network of subterranean passageways lies tangled beneath Indianapolis' bustling City Market.

Outstanding collection of 19th century medical instruments includes a life-size figure cast from as many as 200 cadavers.

One of the few surviving "Wigwam"-themed motels.

Prehistoric animals decorate this popular outdoor park.