A massive concentration of algae is responsible for this lake's pink hue.

An abandoned marine theme park has created a difficult experiment in dolphin rewilding.

With over 10,000 lights, this engineering marvel lights up the city after dark.

The vibrant buildings in the “capital of the comic strip” celebrate the art form that made it famous.

The world's largest reflecting pool is just two centimeters deep.

The last moments of the ill-fated Pompeiians, frozen forever in plaster.

Foreign invaders almost left this lovely Caucasus palace alone—almost.

Semaphore saints, a golden dragon's head, and a stone carved with religious warnings all call this cathedral home.

An unusual round church in London with a Templar past.

Four steel monoliths stand in the Qatari desert, in a breathtaking work of large-scale art by Richard Serra.

Robot jockeys ride their humped mounts to victory as part of a 21st-century twist on an ancient desert sport.

A state-of-the-art medical facility dedicated to treating beloved birds of prey.

A misunderstanding gave this 18th-century racehorse a most amusing name.

The final resting place of the father of modern biological taxonomy.

A golden egg-shaped sauna in the Arctic tundra.

This Stockholm art museum integrates many of its pieces into the surrounding outdoor areas and natural landscape.

A temporary art piece to celebrate LGBTQ Pride is now a permanent part of Stockholm's traffic landscape.

There are hidden patterns on the subway seats of some Stockholm metro cars.

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

Stockholm's deepest subway station is also a stunning ecological wonder.

One of the world's first dedicated bank buildings in the world is now the oldest one.

Stockholm's narrowest alley is barely over two feet wide.

This small museum nestled inside a souvenir shop is dedicated to Sweden's most well-known toy.

A king's bloodstained shirt is among the gruesome collection of artifacts displayed below Stockholm's Royal Palace.