This medieval footbridge in the Swiss Alps is known to attract cliff-jumping daredevils.

Rumors and legends of secret Nazi activities surround this eerily remote island mansion.

A whimsical bridge adorned with decorative dragons.

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

Pay your respects to a country that only existed for a few weeks.

Scenic hike to a restored watermill.

A perfectly preserved hill village where the buildings are painted like white lace.

This fresco-covered medieval monastery hangs from the side of a steep cliff.

The smaller of the three towers of San Marino is a former prison inaccessible from the ground level.

Building owners can take out tiles for free at this repository for historic building materials.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

Polish luminaries and masterful folk art find sanctuary in this unique cemetery.

This Nazi ruin was the site where Hitler was almost blown up by a suitcase bomb.

The two abandoned overpasses are among the largest bridges in Poland.

A small granite monument marks where the borders of three countries meet.

This 22-floor tower's Skydeck offers panoramic views of Amsterdam.

Rich with fauna and flora, nature-lovers can walk across the sea at this UNESCO World Heritage spot.

Its town washed away centuries ago, this lonely tower by the sea tells the tale of a mermaid and a curse.

A beautiful maze marks where three countries meet.

Artists made this mosque into a marvel of Ottoman baroque architecture.

Depending on the region's rainfall, this church may be partially submerged.

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

A curious little museum dedicated to the furry feline in the cat haven that is Old Town Kotor.

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