The oldest inn in Kilkenny was established by the first convicted witch in Ireland.

Two volcanic lakes in an enormous crater formed in a prehistoric eruption.

Climb right into the heart of this colorful Iceland volcano.

A winding, blood-red tunnel of hardened lava navigable by foot.

The hottest place on the planet.

Rock-hewn monastery complex with hundreds of cave structures tucked away into the mountainside.

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

This bazaar is one of the oldest in the Arabian world.

A sinkhole and now a swimming hole, too, full of dazzling turquoise water.

An unusual cave filled with rare alien-looking aragonite formations.

Climb around the high waterfalls on series of iron ladders and bridges within the wildest gorge in the Slovak Paradise.

A tiny church on a man-made island in the Adriatic.

This exclusive resort has completely covered a tiny Balkan island in a 5-star warren of guest rooms.

A curious cave church carved into the face of a cliff.

These historic defenses ensured the city within would survive hundreds of years of occupations, sieges, and invasions.

One of the world's oldest olive trees, thought to be over 2,000 years old.

One of the world’s largest and deepest freshwater springs, where mastodons once roamed.

More than 2 million Olive Ridley sea turtles are hatched from this mass nesting ground every year.

This portion of a lovely Belize beach is infested with (harmless) sharks and rays.

A factory director designed what was the world's longest suspension footbridge in 1923 so his employees could get to work safely.

An Italian geologic wonder that served as the inspiration for the landscape of Dante's hell.

The Sighignola summit on the Swiss border offers views so breathtaking it's been named one of the most beautiful places in Italy.

Crushed coral and crystals give the sand its signature coloration.

These delicate sand pyramids look like naturally occurring gothic spires.