The largest of London's subterranean rivers and once a mad, bad center of London life.

A statue marks the exact spot where The Boy Who Never Grows Up made his first literary appearance.

Scattered throughout London are ancient remnants of the city's former bounding wall.

A cluttered and astounding collection of antiquities and curiosities.

This 1920s Dutch barge is now a floating bookstore.

A tongue-in-cheek arcade where the games are based on everyday life.

An easily overlooked stretch of ornate window fronts and gaslight lamps that could be right from the pages of Dickens.

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

This unique architectural wonder is also tied to one of the 20th-century's most renowned writers.

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

It took 82 years and four different plaques to finally get the story right.

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

This museum is dedicated to the most famous Irish writers in history.

Once an early Christian burial site, it's believed the location was home to around 200 gravestones.

Horse cemetery on the grounds of Blarney Castle.

The ruins of a sixth-century monastery sit on the banks of the River Shannon.

An elaborate Romanesque archway, built right before the British occupation of Ireland.

The ruins of a monastery that dates to the 7th century.

The remains of a concrete ship sit on a sandbank between Ballina Quay and Belleek Woods.

The largest stone circle in Ireland.

The remains of a majestic house that was once stood in the crosshairs of the Irish Republican Army.

Originally built to monitor fishing, this Victorian tower now educates visitors about the local salmon industry.