5,000 skulls in memorial to those killed by the Khmer Rouge.

Bombed and burned, this monument represents the often controversial ties between Vietnam and Cambodia.

One of the biggest markets in Asia, under one of the continent's largest domes.

A tiny rural community in Switzerland was home to one of history's most shocking murders, and led to the banning of Absinthe for nearly a century.

The silly symbol for an underground protest group is now scattered around the city.

3,000 market stands in five former Zeppelin hangars.

Op-art architecture designed for happiness.

A whimsical bridge adorned with decorative dragons.

The Polish capital has had a deep connection to its guardian mermaid for almost a millennium now.

The prototype for all Nazi concentration camps.

Eighty million natural history specimens call this gargantuan museum home.

A hands-off space for graffiti artists to hone and display their skills.

One part local history, 99 parts gruesome haunted house.

Banksy gives themself artistic license with this piece of London street art.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

Rare documents, old instruments, and gruesome specimens showcase the history of military medicine.

A surreal pile of colorful junk fills a small yard in an otherwise gray neighborhood.

Dark, eerie exhibits make for a surreal exploration of the subconscious.

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

A 250-year-old timepiece-automaton adorned with golden mechanical birds, which still sing to this day.

The oldest museum in Russia is home to a fascinating collection of nearly two million anthropological artifacts and anatomical curiosities.

Some Moscow residents once claimed the bizarre, contorted mass of metal on top of the building was used to manipulate minds.

One of the world's tallest statues is also one of its most hated.

This newly renovated Soviet-era outdoor exhibition center is bigger than the principality of Monaco.