This abandoned iron furnace was one of the first to use coke—a type of high-carbon fuel—to make iron.

This jaw-dropping 19th-century bridge uses its reflection to form what appears to be a perfect circle.

A sacred site for Native Americans surveyed by George Washington and owned by both King George III and Thomas Jefferson.

An Albanian monument to the Communism that nearly crushed the country is now a crumbling wreck.

The largest Roman amphitheater in the Balkans once held over 20,000 people, but managed to lay hidden for hundreds of years.

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

Once an opulent Art Nouveau hotspot, the Constanța Casino is one of Romania's most beautiful abandoned buildings.

Nine centuries-old fortresses guard the walls of this medieval Romanian city.

This hauntingly beautiful cemetery outside a medieval citadel is full of winding paths and ivy-covered graves.

The possible imprisonment of Vlad the Impaler here earned the medieval castle its nickname, "Dracula's Castle."

Moss and stone turn this waterfall into an otherworldly liquid veil.

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

Caves that can't seem to quit producing the remains of prehistoric humans.

Home to some of the oldest hominid fossils ever found.

Beloved children's TV characters freckle the German city's streets.

A Neolithic celestial calendar standing in a nondescript wheat field.

Take a hike to this unique rock formation formed by lava flows.

Legend holds eating just one of these black eggs can add seven years to one's life.

Old Tudor home moved on thick iron rails to a new spot.

At just 25 inches at its narrowest point, it's one of the tightest streets in the world.

Now nearly dry, this lake is said to be the ancient home of the Lady of the Lake, and was once thought to be bottomless.

A fantastic castle rumored to be the birthplace of King Arthur.

It is said the legendary wizard once lived in this sea cave beneath Tintagel Castle.

The world's largest collection of witchcraft regalia.