The youngest volcano in Central America.

One Costa Rican island is so beset by illegal shark poachers that the local rangers have built an entire bridge with their confiscated gear .

This collection of historical artifacts and tropical wildlife waits just beneath the surface of the water.

Known as one of the most famous parks in Honduras.

This staircase full of Mayan hieroglyphics is perhaps the largest single text in the world.

A hidden alley in urban Baltimore is a haven for graffiti artists.

A blank headstone topped with a pile of pennies marks the final resting place of the infamous assassin.

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

An abandoned church gets a second life as a massive beer hall and event space.

Inside the world's largest seed bank, WWII botanists elected to starve to death rather than compromise their collection.

The Fox Sisters, America's leading mediums in the mid-19th century, possessed a table they claimed helped them "communicate" with the dead.

Soaring over the Niagara Whirlpool since 1916.

The remnants of a wooden-hulled fleet built and abandoned in WWI, now home to a thriving ecosystem.

At this former Prohibition speakeasy, electric birds signaled the arrival of hooch.

This free, take-a-book shop seems like a trick but isn't.

This abandoned asylum was once a state of the art facility before devolving into one of the most deadly mental institutions in American history.

A magnificent waterfall is also home to the remains of a Roman hydraulic engineering system.

A forgotten "city of water" underneath the famous Trevi district.

This large, circular tomb is the final resting place of the first emperor of Rome.

This beautiful park on the outskirts of Rome protects the ruins of two colossal ancient aqueducts.

2300-year-old Roman road connecting the empire.

Spanning the El Chorro gorge, this pathway used to be one of the most dangerous crossings in the world.

Rare karst landscape eroded from a flat seabed.

This abandoned mansion has a window for every day of the year, and is a temple for ghost hunters.