William Blake claimed to have painted this gothic masterpiece after encountering this nightmarish being in a vision.

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

A unique hotel for the artistic soul.

A 400-year-old mummified arm dangles from the ceiling of St. James the Greater, serving as a warning to thieves.

The beautiful baroque library of the Hapsburg empire.

A tropical paradise just a short trip from the opera house is filled with beautiful winged creatures.

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

An otherworldly alpine pasture with its own unique microculture that recalls Middle Earth.

One of the most spectacular bridges in Spain spans a narrow chasm that divides the city of Ronda.

This whimsical castle of grottoes was the labor of love of a French postman, and one of the greatest achievements of outsider architecture.

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

This medieval castle overlooking the Elzbach river looks just like it did hundreds of years ago.

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

A view-altering observatory at the University of Texas.

This small, unassuming street is now a canvas for color and creativity.

These magnificent city walls rise from the barren sun-baked Spanish plains like something straight out of a fairytale.

This odd Chilean waterfall-cano hotel must be entered via a rope bridge.

This incredible college library is a visual masterpiece of mosaic art. It also looks kind of like a giant boombox.

This beautiful natural train tunnel is said to grant the wishes of visiting lovebirds.

A celebration of solstice followed by a fiery purging of evils.

Only a fragment of this 15th-century Dance of Death survives today.

This unique temple complex remains off the typical tourist trail.

Giant busts of 42 U.S. presidents are sitting in a field in Virginia.

Former host to the World Elephant Polo Championships.