A Romanesque sanctuary of calm amid the bustle of downtown Los Angeles.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

The frozen bubbles that form on the icy surface of this Canadian lake contain enough methane to create a small explosion.

This ancient cave is home to a museum, bar, and is filled with fluorescent minerals.

Colorful sand dunes create a unique attraction in this part of Utah's red-rock country.

Ancestral Puebloan ruins, natural arches, and box canyons abound in this seldom-visited corner of Monument Valley Navajo Tribal Park.

The eerie remnants of an ancient forest were hidden under the sand for centuries.

A reproduction of earth's many biomes.

After starting as a whimsical tourist attraction that eventually found its way to ruin, these renovated canals offer a lush and exotic locale on the Pacific Coast.

A modernist landscape of water and sci-fi concrete.

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

Take a drunken tour inside the world's largest known geode.

Crypt mausoleum in cathedral's basement contains relics of third century Roman martyr, Saint Vibiana.

Possibly the most beautiful carillon in the world, set atop Iron Mountain in Florida.

Where manatees are the snowbird vacationers in these balmy Florida springs.

The hike through a narrow river flanked by the 2,000-foot-tall walls of Zion Canyon is one of the best in the world.

Relics of the 1894 Midwinter Exposition continue to delight visitors today.

Enormous lake at the bottom of a unique cave system.

Explore the largest pure gypsum deposit in the world, and go dune sledding while you're at it.

For two weeks every June, fireflies in the Smoky Mountains perform an astonishing light show.

Wondrous sandstone hoodoos where Native Americans collected clay for pottery, 9,000 years ago.

Most-visited and most-photographed slot canyon in the American Southwest.

Rippling sand dunes frozen in the Arizona rock.

A futuristic temple of light uses prisms and rainbows to create an atmosphere of peace.