Colorful curls of hand-blown glass form a captivating tower in San Antonio's Central Library.

The final resting place of infamous outlaw Clyde and Marvin Barrow.

An ivy-covered arch bridge dedicated to Tejano music singer and legend Rosita Fernandez.

The most loyal of little dogs, or a Victorian era publicity stunt?

This otherwise ordinary close on the Royal Mile constituted the end of the world for Edinburgh’s poorest residents.

Overlooked by many, the two famous Scottish warriors guard the main gate of Edinburgh Castle.

The final resting place of soldiers' loyal canine companions.

"Respectful to the dead, safe and sanitary to the living, dedicated to the Genius of Memory..."

Ruined 11th century abbey built by King David I in Edinburgh, Scotland.

17th century streets hidden under Edinburgh were once a breeding ground for the black death.

This picturesque horseshoe weir was first built in the 1600s to prevent flooding in the town of Bath.

Hauled from the water's depths, Henry VIII's flagship is preserved in this capsule-shaped museum.

An architectural oddity hides in plain sight on this iconic London bridge.

The ritual has been performed uninterrupted for nearly 700 years.

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

One of England's most famous churches hides a pair of little known architectural treasures.

A statue of the legendary Celtic warrior queen who fought the Roman invaders stands in one of the cities she once destroyed.

One of the few standing Roman lighthouses and a labyrinth of tunnels are a couple of the secrets at this historic castle.

One of Europe's oldest libraries.

There's an exclusive Beefeaters pub hidden in the Tower of London.

The fierce beast perches atop a pedestal marking where the historic City of London gates once stood.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

Follow the original medieval paths that wind through this intriguing section of the city.

Richard III supposedly disposed of his nephews' bodies here in an effort to seal his claim to the throne.