Notorious artist squat renovated into legal studios.

During the summer months, giant teddy bears take over Paris near Les Gobelins metro station.

The tradition of open-air secondhand and antiquarian bookselling in Paris dates back to the Renaissance.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

Local legend says Isaac Newton built this footbridge without any screws, bolts, or nails.

An extraordinary library and archive dedicated to the history of the Arctic and Antarctic poles.

Meant to be a lavish presidential home, the palace became a symbol of the fall of South Vietnam.

World's largest cave was only discovered in 1991, and now offers tours to the public.

A 19th-century perch for spotting sailing ships now boasts one of the most iconic views in the Southern Hemisphere.

Formerly known as Saville Theatre, this mid-20th-century entertainment hub includes an ornate frieze.

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

Originally built for London’s cab drivers, this bright green hut now serves anyone a hot drink or meal.

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

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

A memorial for public executions that dates back to the 14th century.

The world's longest continuously running show has played at this small West End theater since 1974.

Order a salt beef-loaded beigel at any hour of the day or night at this East End institution.

Down a pint of ale where the Bishop of Ely's servants slept in 1546.

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

This abandoned church in central Lyon is missing its front stairs.

One of the Seven Wonders of the Modern World holds the world's tallest metal staircase.

A book collector's dream, this Toronto bookstore has the world's first "Biblio-Mat," a random book vending machine.

A 98-room castle in the middle of Toronto that bankrupted a 19th century electricity multimillionaire.