A park where people have been going to feed friendly pigeons since the 18th century

Drift through underground caves on a tube.

The short hike is worth the stunning views and crystal blue waters of a secluded beach.

On a small Puerto Rican island, banks of secret naval bunkers lie abandoned and filled with piles of office equipment.

A magnificent waterfall nestled in the heart of the El Yunque National Forest.

The location of Puerto Rico's first water bottling plant, thanks to a collaboration between Mother Nature and technology.

An enchanting natural wonder in Puerto Rico's Camuy River Park.

This niche museum devoted to ancient religious artifacts is shaped like the very thing it displays.

The bat-covered home of one of the world's most popular brands of rum is located on a tropical Art Deco campus.

Rusting, graffiti-covered tanks litter the beach of this island, once used by the U.S. military for target practice.

Just a few miles from downtown Atlanta is a trail covered in a crazy collection of outsider art.

The world's largest vertical wind tunnel.

Wall to wall taxidermy at Denver's oldest and most exotic steakhouse.

A 17th-century bezoar, dirt from an infamous site, and other curios decorate this unusual bar.

An Austrian house of bones filled with hundreds of intricately painted skulls.

Terrifically morbid cemetary and site of famous Paracelsus' grave.

This former insane asylum now holds a pathological anatomy museum.

The final resting place for the remains of 143 Habsburg royalty.

The crypt of the imposing Stephensdom holds royal intestines and thousands of skeletons.

A miniature train-ride through Slovenia's largest cave system.

Some call this eerie forest of crooked trees the "Bermuda Triangle of Romania."

This massive underground salt mine now holds a sci-fi theme park in its depths.

Moss and stone turn this waterfall into an otherworldly liquid veil.

This fairy-tale castle would make Dracula (who is said to have been imprisoned there) jealous.