This tumultuous Icelandic lava field looks so alien European researchers want to use it as a stand-in for Mars.

Yale University's home for rare works, including the mysterious Voynich Manuscript.

A 16th-century horror show built in a lovely Italian garden.

The birthplace of an eccentric alchemist and possible inspiration for the fictional reanimator of monsters.

She asked for a potato cellar and over the next 23 years he gave her a network of holy caves.

Isolated atop this Balinese sea crag is a lovely Hindu temple that is said to be guarded by sea snakes.

Right up until the 20th century this network of man-made caves was the biggest village in Eastern Armenia.

This military mausoleum captures the solemn grandeur that most memorials only aspire to.

This jaw-dropping 19th-century bridge uses its reflection to form what appears to be a perfect circle.

Once the tallest building in the world and the site of "the highest dinner ever held in New York" this building now holds the most expensive penthouse in the city.

Mother Nature outdoes herself with this stunningly beautiful set of caves carved into marble.

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

Comprised of thousands of cave temple carvings this cornucopia of ancient Chinese stone art is unrivaled anywhere in the world.

An English artist has turned an unassuming ex-council house into a time-lost house of mystery.

Storms, funding, and in-fighting have kept this Bermuda church from ever being completed.

A lake with hundreds of ancient skeletons surrounding it. The surprise is what killed them.

A massive underwater sinkhole made famous by Jacques Cousteau.

This Peruvian canyon is filled with geometric salt pools that have been being harvested since the Incan empire.

This former Nazi castle was built as a school to train what would have been the future of the Third Reich.

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

The bluer than blue waters in these natural Israeli caves are reached via the world's steepest cable car.

This massive blockhead sculpture hides an entire library.

This impressive Boston holy house is the American mecca for Christian scientists.

This man-made mound monument was built out of soil from all across the Polish empire.