From Nazi chemicals to the CIA, this architectural marvel has played a fascinating role in German history.

Enjoy the waters of this half-moon-shaped natural pool surrounded by breathtaking scenery.

This former sugarcane transport tunnel is now a portal to a lovely beach.

A prehistoric landscape hidden in the cliffs of Maha'ulepu.

Ten acres of the Kula Forest Reserve make up this wondrous state park.

Inside, visitors are treated to the rich history of sugar farming and its impact on Hawaiian society.

An eccentric park and pool.

Earth's tallest volcano is sacred to Native Hawaiians, and home to a dozen world-class observatories.

The highway's southernmost spot is a beloved local attraction.

Climb to the top of its spiral spire for spectacular views of Copenhagen.

Danish tourist destination well known for open stalls where vendors sell marijuana on the street.

A statue honors the local legend that the devil helped build St. Mary's church after being tricked into thinking it was going to be a wine bar.

A tilted half-timbered house from 1672 is built into a salvaged segment of a medieval wall.

The small alleys in Lübeck's Old Town are a result of medieval urban sprawl.

This contentious squat has stood through fire, violence, and government intervention as a hotbed of leftist protest.

Hamburg's first legal sex work is relegated to a gated street that still does not allow pedestrian women.

Hamburgers are intensely proud of their tunnel beneath the river.

A stunning gilt bronze relief denounced by Hitler as "degenerate art"—even though it was dedicated to the Nazi leader.

Böttcherstraße's bells, extolling Nordic virtues and the great conquerors of the world.

This mine is home to the largest man-made hole in Europe.

A medieval gate once used as a prison and how home to a city museum.

Thousands of tourists and residents in Cologne affix "love padlocks" on the Hohenzollernbrücke Bridge to symbolize their affections.

One of the tallest buildings in Iceland, and perhaps, the most visually impressive.

These engineering masterpieces are a dominant feature of the Belfast skyline.