The granddaddy of all tourist traps, built on ice water, jackalopes, and a giant dinosaur.

The superstar of Cold War nuclear bunkers has been featured in countless films but is now barely operational.

A rare chance to get up close and personal with a 13-mile ribbon of ice near downtown Juneau.

The only natural lake in the world that drains into both the Atlantic and Pacific Oceans.

A beautiful geyser under environmental threat.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

The last physical evidence of the Lewis and Clark trail is one of their autographs etched into this giant rock.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

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

Home of the International Space Hall of Fame.

Twice a year, visitors can tour the desolate site that birthed the Atomic Age.

Twenty-seven massive radio antennas on the high plains of New Mexico search for life on other planets.

Home to the world's largest refracting telescope and the birthplace of modern astrophysics.

A world-class observatory in the California desert.

The world's largest rotating world.

This tiny patch of arid sand sits in one of the greenest states in the United States.

Three and a half miles of cliffs, rocky beaches, Gilded Age mansions and 40 Steps to nowhere in particular.

A 60-room castle constructed by a horse-racing heir.

Oldest synagogue in the United States.

One of nature's most well-scheduled phenomenons resides in Wyoming's Yellowstone National Park.

California's own majestic geyser is powered by a subterranean volcano.

There aren't too many operational funiculars around, but Pittsburgh has two!

Experience a charming 1930s version of "infotainment."

Stepping away from the glitz of mobsters and casinos to learn about the other history of Vegas.