An atomic bomb-proof strongbox protects the U.S. Constitution from terrorists and thieves.

One of the most influential presidents in U.S. history wanted only this plain, elegant monument as his lasting memorial.

A muscular Art Deco monument represents the struggle between regulators and unbridled markets.

An overlooked memorial honoring the local Washington residents who died in World War I.

Look closely and you’ll notice that the color changes a third of the way up the tower.

The monument's pointy aluminum tip has been melted down by repeated lightning strikes.

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

A little marble compass above George Washington's (empty) tomb in the Capitol marks where D.C.'s four quadrants intersect.

From the Difference Engine to the Cray-1, all under one roof.

One of the largest Marian shrines on the West Coast stands rather unexpectedly in Silicon Valley.

An Aladdin's cave of old Silicon Valley tech.

One of the largest free-standing structures ever built, this dirigible hangar is now simply a giant skeleton.

A giant can of fruit cocktail is all that remains of what was once the world's largest cannery.

800 apricot trees honor Silicon Valley's agricultural history.

What was once a presidential estate is now an exotic menagerie and home to the Budweiser Clydesdales.

This titanic oil company sign is a reminder of the Americana boom of the 1970s and also its commoditization.

One of few surviving standpipe water towers in the U.S.

What was meant to be a temporary exhibit is now a permanent fixture at the St. Louis Zoo filled with beautiful birds.

A monument commemorating the role of Alaska's native Tlingit guides in the Klondike Gold Rush.

A historic freight system that found the true gold rush is in tourism.

Holy Grotto of Montserrat Monastery holds one of Europe's mysterious black Madonnas.

Spain's unique Mosque-Cathedral has been a place of worship for both Muslims and Christians throughout its history.

A curious carving hides on a marble column in the Mosque-Cathedral of Córdoba.

A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.