A tiny piece of the Moon is embedded in this stained glass masterpiece.

Home to items never before seen by the public.

The largest free-standing aquarium in the world resides in a hotel lobby in Berlin.

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

A nostalgic bibliographic gem.

Equal parts record-breaking temple to consumerism and bizarre fun park, it's more than you think it is...

An organ located deep within a cave, whose "pipes" are the geological features of the cave itself.

Remnants of the most densely packed city in world history, that thrived on anarchy for 30 years.

The most famous location in China was home to whole dynasties worth of imperial rulers.

A building so large that it has its own weather.

At this Denver landmark, the meals are compulsory, the sopapillas are complimentary, and the insanity is everywhere.

Explore the largest pure gypsum deposit in the world, and go dune sledding while you're at it.

Some of the tallest ancient American ruins continue to inspire awe and curiosity.

Limestone caves with spectacular showcase chambers.

A reproduction of earth's many biomes.

The world's largest military aircraft cemetery.

Established in 1925, Kiddie Park claims to be the oldest amusement park in the U.S. - a cozy little time warp nestled in a shady corner of the modern world.

An 18th century wonder of the world, lost in WWII, re-created at the Catherine Palace.

The past, present, and future of Russia's signature alcohol is remembered in the world's only museum dedicated to the starchy spirit.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

This Memphis recording studio launched the careers of Jerry Lee Lewis, Johnny Cash, and Elvis Presley.

America's post-nuclear-attack chambers of Congress.

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

Mosaics, storks, and brothels—this ancient city has it all.