This irregularly shaped sea fortress has defended not one but three different sovereign states.

The "dragon babies" of southeastern Europe.

A miniature train-ride through Slovenia's largest cave system.

This one-time health resort was used by aristocrats around the world.

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

This micro-nation may be some sort of prank, but its constitution sure seems official.

An old hill fort covered in over 100,000 crosses is a symbol of Lithuanian nationalism and beliefs.

The largest madrasa in Morocco once housed more than 900 students within its exquisite walls.

God's Saharan sandbox of wrath.

Vast stretch of tide-pools with a unique Moroccan charm.

Fortune tellers, snake charmers, poets, and storytellers all gather on this historic square in Morocco.

Thousands of narrow alleyways in an ancient medieval city make up what's believed to be the world's largest car-free urban zone.

An awe-inspiring mosque in Morocco with one of the tallest minarets in the world.

A fortified city, home to a remaining population of five families

One of the most spectacular canyons in the world.

Founded as a refugee camp, now a popular tourist spot.

Morocco's Argania trees are infested with nut-hungry goats.

Inside this metro station is a section of the city's former medieval fortification.

These slanted cubic abodes are a creative if odd solution to a zoning pickle.

Birthplace of the "Cat in the Cradle" and a cluster of iconic, original windmills that let the Dutch tame the seas.

The history and future of cannabis.

This statue once earned the distinction as one of the "Three Major Disappointments of the World."

Climb inside an iron crystal magnified 165 billion times its normal size.

Singapore's landscaping project is home to 18 incredible Supertrees.