This gorgeous reading room houses the oldest and largest art history library in the Netherlands.

Established in 1638 to battle the Black Death, Hortus Botanicus Amsterdam is a treasure trove of rare flora.

The remains of a 37,000-year-old prehistoric society were discovered in this mammoth cave, one of the largest in Asia.

Seven beautiful 1,000-year-old rock-cut Buddhist statues.

An ancient stone fortress considered by many to be the eighth wonder of the world.

A Bohemian "anti-hotel" offers off-kilter stays in Sri Lanka.

A 16th century chapel decorated with bones, skulls, and entire bodies hanging from the wall.

This odd Chilean waterfall-cano hotel must be entered via a rope bridge.

This abandoned Slovenian military barracks has become a punky-political art squat.

A crumbling World War I fort that is reached through a series of concrete tunnels.

The walls of this medieval church are covered with perfectly preserved frescos, including a pristine example of the Dance of Death.

This one-time health resort was used by aristocrats around the world.

This abandoned Belgian fortress is purposefully being left to nature.

A marble Lucifer hides behind the pulpit of this Gothic cathedral.

A 19th century artistocrat's mansion, turned into a library, hidden in a modern library.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

Menacing or in memoriam, the Silent People and their meaning are left to interpretation.

One of the world's most unusual events combines headbanging and needlework.

The tallest lighthouse in the Nordic countries was also the site of a bloody World War II battle.

This abandoned villa of makeshift buildings was once the home of dancer Elis Sinistö.

Finland's oldest astronomical observatory once played a crucial role in seafaring and timekeeping.

Fortifications built for a Soviet invasion that never came now sit abandoned in a losing battle against nature.

Nuclear waste experts study this prehistoric crater lake to envision landscapes one million years in the future.

Architecturally stunning library serves as the hub of Finnish scholarly life and culture.