A Christian monastery stands on what was once a holy Incan temple.

This geometric feat is a testament to the Incas' mesmerizing architectural abilities.

Built on the remains of one the Incas’ most important gathering spots, this square keeps the spirit of a fallen empire alive.

Situated on a sacred Inca site, this 16th-century cathedral took nearly 100 years to build.

This stone complex marks the urban center of a lost civilization.

The so-called "Father of Las Vegas" had the city's first telephone installed in his office in 1907.

It may look like no more than a full-scale model, but every part of this full Space Shuttle stack had a working role in aviation history.

A propulsion engine testbed that paved the way for the Space Shuttle launch sits without recognition at this rocket center.

Bananas are often left for the first monkey America ever recovered alive after being launched into space.

Fans of vintage Vegas, kitsch, and toy pony-based gambling now flock to a casino called The D.

A piece of the iconic wall found an unlikely new home in a Vegas bathroom.

The second-largest gold nugget in existence, displayed in a Las Vegas casino conveniently named the Golden Nugget.

San Francisco's oldest surviving monument and meeting place for 1906 survivors.

A pair of mutilated bronze octopuses slump at the base of the monument honoring California's admission to the U.S.

This concrete tangle of square pipes has stood as a proud thorn in the city's side since the '70s.

Visible below the waves are memorials to the city's Gold Rush dead.

A free, public museum dedicated to the fascinating science of sight.

The only visible piece of San Francisco's most famous shipwreck.

A huge musical instrument played by the ocean.

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

27-room home built with the fortune of a sugar magnate.

Half of a house.

The tea room that pushed the boundaries of adorable straight into...we can't find the words.

This Japanese treats shop may have been the first business to mass-produce fortune cookies in the United States.