This Florida sinkhole hides a rainforest-like micro-environment in its depths.

Stay in a room with a view... of the bottom of the ocean.

An underwater city for the dead.

World War II-era bunkers are hidden under the beaches of this picturesque park, which is still scattered with wartime watchtowers.

A desiccated merman and a walrus penis bone are among the oddities in this eclectic collection of shipwreck treasures.

This splendid Versailles-inspired mansion has the largest French-style formal gardens in North America.

Underground tunnels remain beneath this abandoned mental asylum.

This museum holds a fully-functional replica of the "Turtle," the first American submarine ever built.

A museum dedicated to antique toys, collectibles, and nostalgia.

A castle inspired by medieval architecture is hidden in the woods of Connecticut.

These etchings reveal the history of a long-gone quarantine site.

New Preston and Kent, Connecticut - where Friday the 13th, Part 2 was filmed.

The world's largest public collection of PEZ memorabilia.

An abandoned Depression-era zoo hidden just off the highway.

Inside this casino, visitors are treated to slot machines and a rare German Christmas pyramid.

A tribute to Loveland’s most famous sweethearts, who helped spread cupid’s message to millions.

This statue of an obscure comic strip hero stands as a tribute to patriotic service and a cautionary tale about embracing fads.

A museum of natural history, Edwin Carter's original log cabin home and workshop houses taxidermy specimens.

Once a lonely sentinel on the edge of the Great Plains, this rebuilt trading fort offers a glimpse of life on the Santa Fe Trail.

Paleoamericans built these ancient walls high in the Colorado Rockies as part of an extensive hunting system.

One of few remaining antique carousels with stationary animals in the U.S.

The site of the "Bone Wars" between two rival paleontologists during the dinosaur rush of the 19th century.

A seven-story 1920s mausoleum outside Denver houses thousands of remains.

A river runs through this remote valley in a very unexpected way.