Arguably the best example of an authentic Dutch windmill in the United States, rivaling its counterparts in the Netherlands.

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

This historic Amsterdam bar used to accept sailor's monkeys as payment.

The attic of a four-century-old canal house hides a clandestine church.

Bizarrely shaped rock formations in northwest Bulgaria come with equally bizarre legends.

A Bulgarian monument to Russia's role in World War II is constantly being painted in pop culture protest.

Mysterious standing stone formations looks like a petrified forest.

Civil War soldiers, captains of industry, and paupers all interred on historic grounds.

Secret gardens just a few miles from downtown Atlanta.

This small cemetery is all that remains of Atlanta's first Black communities.

The beauty of urban decay, hiding some dark secrets.

An underground magnet for ever-changing street art.

The largest hewn stone in history.

The industrial monstrosity known as Bagger 258 is a colossal mining machine built in the DDR - but now left for dead in a German field.

Two stunning 17th-century libraries and a cabinet of curiosities.

The history of occult science is turned into a creepshow at this lurid Prague tourist attraction.

Stone age urban planning.

A giant portrait of an ancient king looms over the river.

One of the oldest churches in Romania is believed to have been built on the site of a pagan temple.

A Romanian church built from one single oak.

An ancient Thracian city where fire rituals were practiced on the largest cult altar in Southeast Europe.

A Turkish monastery tucked into a cliff wall.

Once described as the "Eagle's Nest," this ruined ancient city rests on a remote mountaintop.

The largest Neolithic ruins in the world hide a notably clean prehistoric metropolis.