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

A massive explosion that leveled hundreds of buildings in the city of Leiden is remembered by a waterside plaque.

Graffiti covers the walls of a room where university students through the centuries have waited nervously to defend their theses.

Devious political maneuvering and four ancient, working telescopes are central to the world's second-oldest observatory.

The works of poetry's biggest names grace the walls of the city of Leiden, all carefully painted by hand.

A 'living museum' in Leiden, the oldest of its kind in the Netherlands.

A treasure trove of Renaissance-era funerary art in a Roman church built on top of Nero's grave.

2300-year-old Roman road connecting the empire.

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

The yawning maw of this pagan visage is said to bite off the hands of liars.

Rome's semi-secret peephole vista is also a former Crusader stronghold.

The medieval home is still engraved with the symbol of the profession, an eye flanked by two axes.

The world's most active stratovolcano is almost always erupting.

Abandoned village in Sicily built during the agricultural reforms of Mussolini.

An abandoned shopping gallery built during Fascist Italy tucked in the center of Palermo.

A study of Fascist era Art Deco design in Italy.

Haunting graffiti left by prisoners of the Spanish Inquisition.

This Arabesque Italian castle was built with a primitive, if ingenious, air-conditioning system.

Every inch of this chapel is covered in craftsmanship from across the world.

Cave shrine on Monte Pellegrino.

This massive glowering Lenin head gazes out over eastern Siberia.

Replica of mosque destroyed by Russia in the 16th century.

Russia's own leaning tower was built on a tragic historical fable.

An unused hyberbolic electricity pylon kept as architectural monument.