This bleach-white graveyard overlooking the ocean is accessed through a tunnel.

A Lovecraftian altar of nightmarish bronze chairs sits ominously on a boardwalk in Puerto Vallarta.

A sculpture dedicated to the trade that gave the town its name.

Few of the many visitors to this resort town know of its hidden Maya ruins.

Current docking place of the SS United States, the fastest transatlantic ocean liner.

Yo, Adrian!

Dr Barnes' $25 billion private collection of art and arboretum.

A tour de force of a fountain, memorializing a man who loved fountains more than anything else.

The sounds of the world's largest fully functioning pipe organ dazzle shoppers at a Philadelphia Macy's.

The first American department store, and home to the largest operating musical instrument in the world.

This elaborate towering structure was once famed for its revolutionary height.

Huge masonic hall in Philadelphia with lavishly themed rooms.

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

Beneath the southern end of the Golden Gate Bridge is the “Gibraltar of the West Coast,” a fort built to protect the San Francisco Bay from naval attack.

Concrete strongholds stand guard over the Golden Gate.

California's own medieval Italian castle, authentic down to the 300-year-old iron maiden in the dungeon.

A poignant memorial to a young boy whose death spurred a dramatic increase in organ donations in Italy—dubbed the "Nicholas Effect."

Clean, cold drinking water flows from a nondescript pipe in a roadside rock face.

This WWII-era military installation once held an entire city within its walls - now, its walls are falling down.

A farm in New Jersey grew a most unusual crop for AT&T's testing purposes.

A gift from Japan, 17th-century lantern stands among the cherry trees at D.C.'s Tidal Basin.

The tunnel under the Capitol Building where Congress takes out its trash.

Disks are rolled out onto the south lawn to absorb the impact of Marine One's wheels like giant coffee coasters.

The National Park Service’s best-kept secret with views that rival any in D.C.