This volcanic crater lake is renowned for its perfectly round shape, stunning blue-green waters, and unique geological properties.

Debatably clever, or just plain honest hotel advertised as "The Worst Hotel in the World."

Rejoice at Amsterdam's ‘pop temple,’ a former church reborn as a raucous music venue.

Island where motor vehicles are banned -- home to the only carless highway in the United States.

Monasteries on rock pillars, once accessible only by frayed ropes.

This old Soviet gas station is in perfect condition, one of the best-preserved mosaics in the country.

Ospreys visit this location every year to nest.

One family's environment-friendly hobbit-house in Wales.

The verdant mossy ruins of a Franciscan monastery lie in the remote Sintra hills awaiting exploration.

The remains of one of Wales’ great medieval buildings, with a pub in the cellar.

This former Welsh metal factory is now a lovely abandoned relic but was once one of the industry's world leaders.

An amazing collection of curiosities hidden in a small Welsh village.

Legend has it that this stone moves down to the river sometimes to have a drink.

These spindly, stone-capped formations are the product of glacial deposits and thousands of years of erosion.

What looks like an ordinary house from the outside is actually a rotating sculpture.

This subway station is named after a local legend about supernatural dancing cats.

Every September, international competitors flock to the flooded quarries of a tiny Scottish island.

Mysterious tombstones thought to be remnants of Atlantis.

This weird, elephant-shaped rock also hosts two ancient tombs.

At an estimated 3,800 years old, this olive tree is one of the oldest on earth.

You can still see the remains of a sacred 3,000-year-old cypress.

A Soviet era flat that refused to conform to the dull gray standards.

An underground city beneath Krakow's postwar socialist utopia.

This uber-quaint Polish village is known for its habit of painting elaborate floral motifs on just about everything.