The world's northernmost aquarium looks like it has fallen over.

A series of modernist treehouse hotel rooms grace the outskirts of an Arctic forest.

The second oldest anatomical theater is housed in a museum of curiosities.

Apartment complexes built into huge repurposed natural gas tanks.

A spherical "micro-nation" in the heart of Vienna.

Op-art architecture designed for happiness.

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

This former insane asylum now holds a pathological anatomy museum.

The Habsburgs' royal collections of art and wonders.

Museum devoted to the artificial language of Esperanto.

Baroque celebration of the end of the Great Plague of Vienna.

A small museum filled with over 1,000 clocks, and one particular clock calibrated to run until the year 9999.

The first overseas server for Facebook in Sweden's tundra.

One man's exploration of the human form, including the bizarre and delightful "Man Attacked by Babies."

An empty relic of the Moscow Olympics crumbles away in Estonia's capital.

A subterranean house of worship carved right out of the bedrock.

A lovingly curated curio shop in which the taxidermy wear newspaper party hats, and peanut shells are spread across every surface.

A giant gorilla made of used car tires used to sit sentinel over a Helsinki college campus.

Single runway interrupted by a busy road that cuts across its middle.

Few other hotels can rival the grandeur of the Castle in the Rockies.

As if T-rex wasn't big enough, this Canadian monument is four times larger than the real thing.

An abstract monument to a symphonic composer.

A collection of collections ranging from dentistry to minerals.

Handsomely crafted representations of our round planet.