Collection of nearly 500 concrete figures sculpted by the late Veijo Rönkkönen.

Legend has this precariously placed rock was placed by giants. Science has another explanation.

This Slovakian statue of an emerging sewer worker might just be a bronze peeping tom.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

One Portuguese poet described this cape, the westernmost point in mainland Europe, as "where the land ends and the sea begins."

In the middle of a Vienna square, Roman ruins dating back some 2,000 years are on display.

The medieval "dragon" on an Austrian city's coat-of-arms comes to life in a fountain.

The world's oldest known salt mine.

Giant WWII fortresses that fired 8,000 rounds a minute, now home to thousands of pigeons.

Vienna's giant wonder wheel had a starring role in one of the greatest noir movies of all time.

Apartment complexes built into huge repurposed natural gas tanks.

Vienna's underworld of tunnels and subterranean rivers made an iconic appearance in a 1949 Orson Welles film.

Beautiful Austrian natural history museum with carved ceilings and row after row of ancient taxidermy.

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

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

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

Single runway interrupted by a busy road that cuts across its middle.

The bizarre visions of H.R. Giger, tucked away in a Swiss medieval city.

A labyrinthine underworld of tunnels and caverns hides beneath the city.

The oldest inn in England served brew to the crusaders.

Tubing through a cave lit with glowworms is a magical underground experience.

Major tourist destination known for its bubbling mud-pools and hot thermal springs.

A Maori village obliterated by an 1886 volcanic eruption.

This electric green sulphur lake in New Zealand looks like a cartoonish radioactive dump site.