The perfectly named cave drop is the deepest in the continental United States, almost matching the height of Seattle’s Space Needle.

Visit this playground of waterfalls, caves and sinkholes.

Labor provided by Great Depression-era programs restored these 25,000 acres in Tennessee.

In the loving memory of a tragically deceased role-player this Illinois park is decked out with both dungeons and dragons.

More than five miles of underground passageways.

This odd stone memorial remembers a loyal dog who offended the rail barons with his speed and saved his master with his pee.

Taxidermy, Cigar Store Indians, A Model of a New York Tenement and Delicious Draft Root Beer.

Eight rare Corvettes are swallowed up by a sinkhole in Kentucky's National Corvette Museum.

Veritable museum of 20th century country music history.

Every last book in this bookstore is signed by the author.

A 56-foot tall statue of the god of fire looks out over Birmingham, Alabama.

River pirates, murderous bandits, and serial killers used this Illinois cave as their debauched hideout.

A unique book shop with a collection of rare tomes and a nostalgia museum.

An enormous natural sandstone bridge in Kentucky.

One person's lost luggage is another person's treasure.

This natural wonder drops 16 stories straight down through rare flora and streaming waterfalls.

Planes, trains, and automobiles have all been sunk as attractions at this Illinois diving spot.

This park contains one of the largest concentrations of cedar glades, a unique and rare ecosystem.

Victorian-era Egyptomania left its mark on this Nashville landmark.

This award-winning men's bathroom was just too beautiful to not allow women to see.

A miniature city built by a single hunchbacked monk.

148 feet long and in the middle of a verdant forest.

Famous for its bio-luminescent inhabitants, known as "dismalites."

The secret city built by the Manhattan Project.