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

Spanish architects used seized Muslim gravestones to rebuild parts of the fortress.

Pick up this rock and become an instant legend.

The picturesque birthplace of Icelandic democracy is drenched in the blood of its brutal past.

In Northeastern Iceland lies something of an oxymoron: a steaming desert.

This scenic Icelandic lava flow is named for a pair of Berserkers who were murdered, according to a famous Saga.

A sulfuric martian landscape that looks far better than it smells.

This black church sits alone among a field of lava rock.

A formerly glacier-tipped volcano that inspired none other than Jules Verne.

This wrecked airplane has been sitting on a black sand beach since the 1970s.

This natural Icelandic fissure allows divers to swim right between two volatile tectonic plates.

If a glacial river suddenly diving into a sheer chasm via a dramatic, multi-stage waterfall isn't peak Iceland, it's certainly close.

This valley of hot springs and boiling mud pots is home to the record-holding "Geysir," which originated the English word.

The most powerful waterfall in all of Europe.

This elegant arc of a waterfall marks a religious turning point.

Walk in the footsteps of the gods and straddle two tectonic plates.

Iceland's largest lagoon is home to stunning multi-colored icebergs.

One of the tallest buildings in Iceland, and perhaps, the most visually impressive.

Cliffs that hold fossils, including the earliest known reptile, dating back more than 300 million years.

Mrs. Mallard and her brood are a beloved fixture in Boston Public Garden.

The site of Paul Revere's historic two lantern warning.

Chicago's Navy Pier on Lake Michigan was a training hub for aircraft carrier pilots during WWII.

Each of these gorgeous, intricately decorated rooms is painstakingly crafted to the scale of 1 inch: 1 foot.

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.