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

The world's largest reflecting pool is just two centimeters deep.

This Bordeaux parking garage has 712 indoor spaces, and one outdoor.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

A hidden three-foot-wide house separates these two regal churches.

The stunning interior of this Gothic church is covered in ornate gold details.

This giant sculpture made of trash is a critique of society's wastefulness.

An eerie collection of the surviving structures from a past celebration of the future.

Spain's largest bullring offers a unique glimpse at architecture and history.

The world's largest wooden structure.

Hidden behind a wall, Spanish nuns distribute their signature sweets on a revolving tray.

Spain's unique Mosque-Cathedral has been a place of worship for both Muslims and Christians throughout its history.

A curious carving hides on a marble column in the Mosque-Cathedral of Córdoba.

Touching this little fossil embedded in the wall of a grand mosque-cathedral may make your wishes come true.

A quarry cum sculpture park where the works of art are chiseled into the very walls.