This abandoned Slovenian military barracks has become a punky-political art squat.

This massive subterranean fissure is known as the "underground Grand Canyon."

Castle and secret tunnel withstood a siege until its owner was killed by the Holy Roman Empire, while sitting on the toilet.

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

Hidden up a dusty track off the Georgian Military Road is this fascinating waterfall with mountainous views.

The cave holds a spectacular array of stalactites and stalagmites, including one shaped like a giant human heart.

The decaying remains of a once-luxurious Soviet spa town.

Unusual building appears to be haphazardly built from randomly piled bricks.

You'll find just about anything in this funky Tbilisi flea market.

Ancient rock-hewn town that witnessed key events of Georgian history.

Underground monastery and fortress.

Take respite inside this jaw-dropping church while climbing the volcano where Georgia's Prometheus was once chained.

A secret climbing tree hides along the side of a Costa Rican road.

Dine inside a giant caterpillar at this community-run eatery.

In Costa Rica's cloud forest, the roots of a woody ficus create a botanical bridge.

Disused penal colony features prisoner artwork, some sketched in human blood.

Once the foundation for a mansion, these ruins now offer amazing panoramic coastal views.

The sister plane of the C-123 shot down during the Iran-Contra Affair has found a new purpose in retirement.

This Costa Rican topiary park is a surreal garden of unearthly delights.

Sparkling, calcite-covered skeletons of children who may have been sacrificed to appease an angry god.

This wonderful rock formation constitutes the first geopark in Uruguay.

The oldest café in Montevideo preserves its history as the city's bohemian hub.

This South Pacific volcano has been blowing its stack for over 800 years and is said to be home to a cult leader waiting to be reborn.

Plains of ash and pair of semi-active volcanoes contribute to the otherworldly beauty of this little-known Vanuatu island.