This picturesque medieval monastery guards a small trove of historic treasures.

The complex has been abandoned since the Croatian War of Independence, barring a stint as a set for 'Game of Thrones.'

Where the lovelorn find a home for their sentimental keepsakes.

Once the fallout shelter of a dictator, this sprawling bunker is now a combined history museum and contemporary art gallery.

The elliptical citadel resisted the advance of the mighty Ottomans several times, thanks to the military prowess of the "Dragon of Albania."

Former hunting lodge of a duke who was an avid collector of impressionist works.

This medieval tower is all that remains of the castle where Joan of Arc was held before being burned at the stake.

This enormous "cloth of the conquest" depicts the Norman invasion of England in mind-blowing detail.

This remarkable museum sprung from one of the most important prehistoric archaeological sites in the world.

A reproduction of the famous prehistoric cave paintings is hidden underground at the National Archaeological Museum.

The library houses an incredible collection of some of the world's most impressive books and manuscripts.

The "lost friend” is the most famous of the six moai statues that were removed from Easter Island.

London's last remaining public soapbox site has seen speeches from Karl Marx, Vladmir Lenin, and George Orwell.

The popularity of Sherlock Holmes led to the creation of his fictional address, turning the orderly London street numbers askew.

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

It took 160 years to complete the most ornate church in Ecuador.

This restored colonial house was once home to the botanist responsible for bringing avocados to the U.S.

A collection of heirloom roses tucked in a spectacularly beautiful botanical garden on Lake Atitlan.

Deep in the Guatemalan jungle stands an ancient pyramid that once marked the reign of a king.

Central America's deepest lake is actually a volcanic caldera, surrounded by three volcanoes.

Three small rooms in the jungle house the most elaborate and intact murals of the Mayan world.

The meteor that sealed the fate of the dinosaurs landed at this site, one of the largest impact craters in the world.

Clap your hands at the base of the pyramid, and the song of a sacred Mayan bird will echo through the air.

No telescopes, no power, no gift shop: The Observatory of Chichen Itza, one of the world's oldest observatories, takes astronomy back to basics.