An ancient instrument used to measure the waters of the Nile so Egyptian farmers would know whether to expect famine or flood.

A house of bones — but nobody is quite sure to whom they belong.

The world's greatest slide descends 18 stories from this looping mountaintop viewing platform.

An enormous, inside-out glass globe built in 1935.

A trio of giant wooden megaphones turn up nature's volume in this Estonian forest.

An exquisite tunnel of cascading flowers.

Roman ruins top white travertine terraces formed by ancient hot springs.

The fairy tale castle of the "fairy-tale king."

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

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

The beautiful baroque library of the Hapsburg empire.

The giant scales in this museum can still tell if someone is one of the devil's brides just by weight.

This neon lit Georgian cave claims to hold the boulder Prometheus was chained to.

The most metal church of all time was built in record time because of an international, pious pissing contest.

This Tuscan lake hides a 13th century town that is still visible when the water recedes.

Life in this isolated, hilltop lighthouse was lonely, but it sure was lovely.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

A metal tree emits eerie, melodic notes on top of Lancashire's Crown Point.

The decaying ruins of Wales' first asylum for the mentally ill.

What once sat in the world’s spotlight is today a largely disused ghost complex.

This replica of the Greek structure is in the heart of Nashville.

A sprawling collection of books and manuscripts about ancient Greece that would have put their famed libraries to shame.

Over 2,000 ancient temples dot the Myanmar landscape at the site of this famed archaeological site.