This noble mash-up in eastern Luxembourg is part Medieval, part Renaissance, all castle.

A collection of huge Pre-Colombian structures in Alabama.

This architectural triumph is the only Frank Lloyd Wright house in Alabama.

This eye-popping Icelandic crater lake is surrounded by red volcanic rock.

Despite time, colonization, and the brutal New Mexican heat, these Pueblo ruins still stand.

These ominous lava formations were said to be an entrance to the netherworld so of course they inspired a famous metal band.

This historic cliffside mansion uses a natural cave for air conditioning.

This star-shaped military outpost is now simply trying to protect itself from neglect.

Iceland's "Smoky Valley" is a beautiful river that is shrouded in a constant cover of steam clouds.

This unreal Portuguese palace looks as though it's made from a pile of different castles.

A small metropolis of Pueblo cave dwellings have been carved right into the hillside of this national monument.

This crumbling Portuguese ruin overlooks the populace it once ruled.

Collecting 700 years of mechanical death-dealing, the NRA's sprawling gun museum is a revealing testament to the American obsession with armament.

This stone complex marks the urban center of a lost civilization.

The remains of what was the most important religious complex in coastal Peru for over a millennium.

Nazca pilgrimage site covering 370 acres is a popular stop for archeologists and looters.

Death rituals and sacrifice inside a Peruvian megalith.

The intricate stonework of Machu Picchu serves as a testament to Incan engineers.

Frank Lloyd Wright's most iconic home dangles over a Pennsylvania waterfall.

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

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

The unique waterfall in Iceland's south features a backdrop of geometric black lava columns.

The Icelandic Sea Monster Museum explores the area's history of aquatic cryptid sightings.

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