According to legend, this tomb holds the secrets to time travel.

Winding paths and ramshackle mausoleums in the oldest "park cemetery" in London.

This enormous gold Buddha statue was hidden inside a stucco decoy for centuries.

Underneath this Byzantinian church lies a necropolis filled with ancient tombs and the ruins of previous churches.

A striking symbol of the Bulgarian capital.

A pair of club-wielding guardians stand watch over London's first public clock to feature a minute hand.

Sofia's legislative center is continuously reinventing itself.

A vast Communist-era exhibition space in the Bulgarian capital.

A collection of art from Bulgaria's time as a communist state.

"Holy Wisdom" overlooks the city that became its namesake.

A retirement home for soldiers that can trace its history to the Elizabethan era and beyond.

This former KGB building is now a museum memorializing the people who suffered during the Soviet regime.

Plaques celebrating Lithuanian writers freckle a wall of this picture-perfect path.

The world's oldest surviving music hall was also once a freakshow.

An angelic, yet demonic-looking figurine presides over one of Glasgow's most ancient streets.

A unique art installation located on what was once considered the widest railway bridge in the world.

Glasgow's memorial to the International Brigade volunteers from Great Britain who fought and died in the Spanish Civil War.

In the depths of Glasgow Cathedral's crypt, one pillar stands out from all others.

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

A scattered trail of street art adds a pop of color to the city's stark structures.

A unique tribute to the millions of animals who served and died for the British military.

Once designed as the entrance to Buckingham Palace, this structure was later relocated and stands as a victory arch.

This landmark church concealed a crypt packed with bones that was discovered thanks to the London Blitz.

The world's oldest operational public pier railway has shuttled seagoing commuters from ship to shore since 1909.