One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

Displaced highlanders would take shelter from the wet Scottish climate under the large walled bridge at Glasgow Central Station.

360° views of the city plus five floors of optical illusions and hands-on science.

This stone harbor was key to Carnlough's limestone industry.

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

This massive monument has been telling the time for 150 years—at a slight angle.

It was once nicknamed "the most bombed hotel in Europe."

The last Victorian market in Belfast.

The only monument to name all of the passengers and crew who died on the RMS Titanic.

The ship built to ferry passengers and goods to the doomed Titanic is now the last remaining White Star Line vessel.

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

This Victorian-era public house has set the standard for pub-style elegance for over a hundred years.

The ruins of this medieval castle in Northern Ireland have inspired artists from C.S. Lewis to Led Zeppelin.

This short bridge is the only thing connecting a tiny Irish island to the mainland.

Northern Ireland's Brobdingnagian stepping stones.

The atmospheric road was never meant to be so creepy.

The medieval woodcut-style artwork chronicles life in medieval London.

The bronze uniforms commemorate the vital role of women during World War II.

The Tudor-style cottage in the middle of the square is not quite what it seems.

This one has sailed five times as far as Sir Francis Drake's famous ship.

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

A labyrinth hides in plain sight at each of the city's 270 Tube stations.

After nearly 60 years, there's still a bear at Paddington Station looking for help.

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