This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.

A pedestrian island in the middle of world-famous Times Square emits a strange (and purposeful) humming noise.

A little sculpture with a large wardrobe.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

Hundreds of hidden passageways weave through the old quarters of Lyon.

Giant marble phalluses on the sacred island of antiquity.

Historic medieval fortified city in southwest France.

The world's largest solar furnace uses 10,000 mirrors to concentrate the sun's rays to generate power.

Go inside to really appreciate this 500-year-old technological masterpiece.

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

Largest lake in Great Britain measured by surface area.

Climb inside an iron crystal magnified 165 billion times its normal size.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

A museum on the history of Paris, including a set of Napoleon's toiletries, Proust's room, and relics of the Revolution.

The celebrated eyesore created by starry-eyed sweethearts.

Bordered by forest on three sides and the ocean on the other, the Great Dune of Pilat is the highest sand dune in Europe.

Famously misunderstood wonder of the ancient world

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

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

Site of one of World War I's most horrific scenes.

This modern French ossuary contains the jumbled bones of 130,000 WWI soldiers.

Statue of a decomposing prince that once held his heart in its hand.

Palace where the nearly un-killable Rasputin was murdered.

A 250-year-old timepiece-automaton adorned with golden mechanical birds, which still sing to this day.