One of the oldest cathedrals in the U.K. houses a priceless early manuscript.

This foreboding medieval castle was twice besieged by barons rebelling against the English king.

The commemorative stone column conceals a secret laboratory.

This sanitized yet surreal depiction of a Greek fertility god looks over a square in one of central London’s residential areas.

Dictionary Johnson’s favorite feline.

A 300-year-old tea shop that brought tea to the English people, not to mention the Queen herself.

A faded reminder of what was once a common sight in London during the Blitz.

This 500-meter-long memorial pays tribute to the hundreds of thousands of lives lost to COVID-19 in the UK.

A hands-off space for graffiti artists to hone and display their skills.

This small shop walked so America could run on Dunkin'.

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.

A lone tower rises above the cliffs in a city park, offering fantastic views of the Connecticut landscape.

A modernist landscape of water and sci-fi concrete.

Built in the 1920s, this co-op in the Bronx feels more like an Italian villa than a typical New York apartment building.

Little Red Lighthouse under the George Washington Bridge.

One of the only single-person private gravesites in New York City.

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

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

A touching tribute to the "Wonky Donkey."

One of the Seven Wonders of the Modern World holds the world's tallest metal staircase.

The 10th-tallest pyramid in the world, this former sports arena is now home to a massive Bass Pro Shops store.

Toxic waste disaster that founded the Superfund program.

City law dictates that this mountaintop cathedral containing the heart of a saint is to remain the tallest building in town.

This crumbling industrial fortress has attracted daredevils, filmmakers, and historians.