No need to strap in for a "ride" on this walkable roller coaster.

This historic stone bridge has an entire neighborhood clinging to its sides.

This medieval castle overlooking the Elzbach river looks just like it did hundreds of years ago.

The fairy tale castle of the "fairy-tale king."

In France, a medieval-style home pays homage to an intrepid explorer who discovered Québec.

This mountain trail inspired Nietzsche to complete his magnum opus.

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

The site of the first medieval crusade that pitted Christians against Christians.

These colorful French islands spent a stint bootlegging booze during American Prohibition.

A unique zoological park home to over 30 species of wild cats, both big and small.

A sublime medieval path adorns the marble floor of one of the most beautiful Gothic cathedrals in France.

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

A remote hilltop covered in giant monoliths haunts the Brittany countryside.

France's high-tech, future-themed amusement park.

This futuristic observatory at the top of the Pyrénées offers unrivaled views.

Hundreds of prehistoric stones, arranged in perfect lines in a French field.

This French castle is said to have once held the Holy Grail but is now a gorgeous mountaintop ruin.

This is what trains will look like after the zombie apocalypse.

The famous winding walk at Chartres is surrounded in mystery and myth.

Historic medieval fortified city in southwest France.

At Monet's beloved home you can still see the Japanese bridge, waterlilies, and weeping willows that were the subjects of some of his most iconic paintings.

An overlooked marble is the only surviving in-place 18th century example of the measurement that changed how we define distance.

Ancient paintings known as the "Sistine Chapel of Cave Art."

Paris' linguistic guide to the international language of, yes, love.