The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

This controversial Irish show cave is home to a massive formation known as the Great Stalactite.

This Irish show cave is said to have been the site of a Viking massacre that claimed 1,000 lives.

This singular Irish dolmen is more Frank Lloyd Wright than upright stonehenge.

One of the largest sculpture collections in the U.K. features history's greats, from Bob Dylan to Galileo, in bronze.

Built by the patron saint of illusionists this Elizabethan manor house is riddled with secret cubbies for hiding priests.

First known as the "Sample House," this construction mash-up was meant to be a living catalogue of building styles.

This secret Australian garden was built on love after a man planted a random bulb he found in the ocean.

The people murdered during a 17th-century Norwegian witch hunt have been honored with a pair of stark, modern installations.

This centuries-old gothic monster has been converted into a sprawling, glossy bookstore.

This tiny lake temple dedicated to a water goddess seems to float on the surface.

This Netherlands museum holds a gloriously mechanical collection of ornate musical automata.

Sitting on an Italian hilltop is this surreal fortress built by the mad inventor of electrohomeopathy.

The abandoned husk of a mental institution that failed to save a Jazz Age icon still sits nearly unchanged.

Macabre astrological automaton clock dating to the late 1400s.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

Northern Ireland's Brobdingnagian stepping stones.

Mirrors and glass shards cover every inch of this arrestingly beautiful mosque.

Go inside to really appreciate this 500-year-old technological masterpiece.

This pair of small sea rocks has been "wed" using rope and ancient Shinto tradition.

A unique waterfall that some believe attracts the fairfolk.

The history of occult science is turned into a creepshow at this lurid Prague tourist attraction.

One of the most remarkable caves in all of Iceland was created by a once raging river of lava.

Learn about Iceland's hidden folk at this school dedicated to the study of elves.