Relics of the 1894 Midwinter Exposition continue to delight visitors today.

A huge musical instrument played by the ocean.

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

Not merely a museum – but a whirring powerhouse that offers a subterranean peek into the heart and soul of cable car operations.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

Museum celebrating the achievements of the Soviet space program.

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

The king of U.S. high points towers over every other peak on the continent.

Former laboratory of radical psychiatrist Wilhelm Reich.

The oldest farmer's market in America is so ancient it was approved by the King of England.

Manhattan and the Bronx have been playing tug-of-war over this former island neighborhood for more than a century.

Surrounded by low rise buildings and partially converted into an auto body shop, this marble archway is the only vestige of a forgotten Manhattan estate.

This was one of the first (and last) university-built and operated nuclear reactors.

Visit the monolithic tomb of America's most famous general.

The highest point on the island known for buildings that touch the sky.

Little Red Lighthouse under the George Washington Bridge.

The oldest surviving bridge in New York City, which reopened to pedestrians in 2015.

The oldest house in Manhattan is now a museum that remembers the home's sordid history of scandals, vice-presidents, and ghosts.

A self-made museum in Queens, New York continues to display the work of a sculptor known for paving his own way.

Hiroshima survivor on Riverside Drive.

A curious fountain that has no water and includes Satan, a crab, and 9 giraffes.

A Natural History and Science Emporium.

This ruined fort hidden at the top of Central Park can't seem to keep from losing its historical plaques.

This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.