An alleyway plaque is all that remains of the independent Texas' envoy that forgot to pay their rent for over a century.

One part local history, 99 parts gruesome haunted house.

The perfectly preserved underground rooms where Churchill plotted the war against Germany.

These official units of measurement—including chains and perches—lie hidden beneath tourists' feet in a popular London hub.

London's smallest police station is barely the size of a phone booth.

Northern Ireland's Brobdingnagian stepping stones.

A museum marks and documents the site of the Titanic's launch.

These engineering masterpieces are a dominant feature of the Belfast skyline.

These barriers stand as stark reminders of Northern Ireland's troubled past.

This Neolithic passage tomb forms part of a World Heritage Site.

This center tells the story of one of the most famous battles in Irish history.

Dublin's most modern, visually spectacular bridge is modeled after Ireland's national emblem.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

The whiskey producer's archives includes a historical list of infractions committed by and associated penalties exacted upon employees.

This staircase in a lush tropical grotto was built by enslaved laborers and renamed to honor Queen Victoria's role in ending slavery in the British Empire.

This limestone cave offers an incredible view of the Río Grande de Arecibo valley.

This giant bronze image of Christopher Columbus embarked on a voyage of its own.

A magnificent waterfall nestled in the heart of the El Yunque National Forest.

This iconic clock tower is the largest in the Philippines.

The largest United States military cemetery overseas.

A Hawaiian stairway to heaven—that you can't climb.

Once the site of the Hawaiian monarchy, this building was originally designed as a palace.

An ode to one of the first concerts broadcast via satellite.

The current Eureka County Courthouse replaced an all-wooden structure that had previously been an ice-skating rink.