The remains of the second-oldest zoo in Europe can be seen within these library gardens.

One of Madrid's oldest trees, with a long and colorful history, resides in El Retiro Park.

Over two centuries old and counting, Madrid's massive botanical garden contains one of Europe's only desert environments.

A statue commemorating a beloved stray dog who was adopted by the entire neighborhood where he lived.

This third-generation institution is one of the last in London that still cures its own salt beef for epic sandwiches.

Order bagels and lox from an iconic Jewish delicatessen with nearly a century of history behind it.

This sculpture encompasses the emotion of rail travel.

Feast on Middle Eastern mezze from an Israeli expat duo.

Soon after its unveiling, this giant inverted globe sparked controversy and was vandalized.

This foreboding medieval castle was twice besieged by barons rebelling against the English king.

The last resting place of the famous Native American princess is marked by a haunting monument.

This star-shaped artillery fort protected the mouth of the Thames from the 16th century to the Second World War.

A marine aquarium with an astounding variety of fish hides in the basement beneath the famous Palm House.

A gallery specifically dedicated to the botanical illustrations of a remarkable traveling lady.

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

The much-beloved mascot of a local museum.

The curious and tiny collection contains some very odd objects.

A monument to the real explorer and bear who inspired characters in Philip Pullman's 'His Dark Materials.'

The arching stretch of London's longest street holds many reminders of the area's maritime past.

Crafted by one of the first makers of stoneware in England.

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

An exercise in radical design and social living that became the epicenter of Soviet spy networks in London.

The canine-themed book collection claims to be Europe's largest dog library.

The world's oldest optical museum is an odd collection where the exhibits look at you.