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

Gold Rush ship-turned-hotel buried underneath San Francisco's financial district.

At 207 feet, one of the world's longest continuous escalators.

The "lovely red Vega" of the legendary record-settling pilot.

A monument in Washington D.C. marks the spot from which all other roads were supposed to stem.

This Yellowstone geyser may not shoot as high as the nearby Old Faithful, but it erupts for considerably longer.

At one time this small mining village was the highest town in America but now it sits abandoned while the mine churns on.

A downtown park built on top of unclaimed graves.

The highest point in Tennessee, Clingmans Dome bears witness to the ravages of one type of insect.

While there are no actual snakes in the history of this crooked road, there may be a number of dead horses.

The world's largest military aircraft cemetery.

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

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

Cold war icon and onetime "hole" in the iron curtain.

The site of the famous Nazi book burning campaign of 1933 remembers its "Night of Shame".

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

The bunker where Hitler took his own life is hidden under this deliberately ordinary parking lot.

Metro station with a claim to rock n' roll fame.

The most visited, and possibly most controversial, museum in Germany.

A beautiful geyser under environmental threat.

Giant, natural amphitheaters made of delicate geological formations called "hoodoos."

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

Here, at the "world's longest art gallery," you'll find forty miles of ancient petroglyphs and pictographs.

This raised bulls-eye visible from space was the subject of an intense geologic controversy.