Vortex-shaped aquarium hosts Europe's largest school of piranhas and other ocean creatures.

Abandoned 19th century homes once occupied by naval officers, soon to be demolished.

The world's first zoo for microbes collecting the horrible and wonderful things living on and around us.

Sandstone rock formations that look like they belong on the cover of a progressive rock album.

According to the local folklore, the myriad colors of this lake are the result of a lovelorn wizard's blunder.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

A waterfall 600 ft. inside a mountain, once the bane of gold miners, is now a spectacle of nature.

A historic house left in "dramatic still life."

Countless stories attempt to explain Poland's mysterious J-shaped trees.

Mural made of 100,000 pieces of hand blown glass, and until recently, the largest glass mural in the US.

Australian Lake set aglow by Noctiluca Scintillans.

Rent out a glass igloo to watch the Northern Lights like you live in the future.

This massive stained-glass masterpiece is thought to be the largest Tiffany dome in existence.

Ride the subways of yesteryear.

These millipedes glow not out of attraction, but as a not-too-subtle warning.

A wunderkammer hidden on the top floor of the Hartford statehouse.

Iceland's "Smoky Valley" is a beautiful river that is shrouded in a constant cover of steam clouds.

Abandoned medieval hill town.

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

This castle was established by the 4th Duke of Montrose and is connected to the Buchanan Clan.

This eye-popping Icelandic crater lake is surrounded by red volcanic rock.

A marvel of Byzantine engineering under the streets of Istanbul.

A mining town once rife with murderous disputes over its copious treasures now creates income as a popular spot for photo shoots.

A collection of abandoned typographic signs from Berlin and beyond.