A sculpture of the famous photograph stands on San Diego's "Greatest Generation Walk."

This iconic L.A. bookshop is housed in an abandoned bank—both symbolic and chic.

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

The world's largest mountain carving could fit all of Mount Rushmore inside it many times over.

The first declared National Monument in the United States.

A walk through the historic city center, under the streets of Seattle.

A crumbling cathedral condemned by an earthquake.

A castle from the Holy Roman Empire that hosts traveling youth... in its stables.

This Dresden church was purposely rebuilt Protestant after being demolished in World War II.

Macabre astrological automaton clock dating to the late 1400s.

Daily jousts and dancing barrel makers in Munich's mechanical clock.

The prototype for all Nazi concentration camps.

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

A multimedia experience that chronicles the atrocities of racism.

Air Force Academy Chapel made of 100 identical tetrahedrons works to inspire those of all religions.

This museum started as a collection of Manhattan Projects and continues to add exhibits as they are declassified.

Quite simply the largest tree in the world (by volume).

Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

A glimpse into the lives of the the Miwok and Paiute people in Yosemite National Park.

This mountaintop beacon is only lit three times a year but shines like some kind of all-seeing eye.

A massive volcanic plug is now a protected area that hosts a number of bird species.

An alley covered with 20 years of bubble gum.

A fitting attraction for the corn capital of the world.

A pop-culture attraction outside of Dyersville, Iowa, hits a home run.