Some of the tallest ancient American ruins continue to inspire awe and curiosity.

The world's largest military aircraft cemetery.

Ancient pueblos built into the base of a natural canyon wall.

A spiritual vortex among the red rocks in Sedona.

An urban laboratory.

This historic national park is covered in the stunning ruins of red rock pueblos.

A motel dedicated to Southwestern nostalgia.

The Magical World of George Phar Legler.

America's only nuclear missile silo open to the public.

Ninety feet off the valley floor is an ancient dwelling put under protection of the U.S. government by Teddy Roosevelt.

A reproduction of earth's many biomes.

See massive fossils that are over 200 million years old in northeastern Arizona.

A self-built castle made by a mysterious man.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

A tiny church on a man-made island in the Adriatic.

These historic defenses ensured the city within would survive hundreds of years of occupations, sieges, and invasions.

Christ's blood preserved in a Belgian town.

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

The solemn exterior conceals an opulent interior of this 17th century church.

Vienna's giant wonder wheel had a starring role in one of the greatest noir movies of all time.

The Habsburgs' royal collections of art and wonders.

Baroque celebration of the end of the Great Plague of Vienna.

Op-art architecture designed for happiness.

Built to give thanks for the passing of a plague epidemic, this cathedral is a one-of-a-kind architectural hybrid.