The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

Staircase winds down the side of Telegraph Hill through gardens, wild parrots flying overhead.

San Francisco's newly reopened hands-on science museum.

A pair of slides and a tree-lined stair corridor have been an urban oasis for nearly 40 years.

Carnivorous plants, medieval aphrodisiacs, and the largest original wood structure glass conservatory in the western hemisphere.

Bring your own cardboard to the slippery slopes of concrete hidden in a neighborhood park.

An artsy hidden staircase leads to breathtaking views of San Francisco.

A psychedelic labyrinth on the San Francisco bay.

A set of outdoor stairs named in honor of a famous Austrian artist.

The resting place for anonymous victims of the Danube's dark waters.

This Austrian museum celebrates the work of famous forgers and their inimitable imitations.

This former insane asylum now holds a pathological anatomy museum.

An ode to a soldier who came to town, fell in love, then began making his own sparkling wine.

A massive sculpture of an obscure Celtic coin that has become a symbol in Slovakia.

A once-fairy tale mansion now stands in a state of disrepair.

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

Sprawled across the Great Hall ceiling are various constellations and images relating to the zodiac.

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

One of the oldest scientific gardens in Britain, containing more than 13,302 plant species in its core collection.

Once a 19th-century brasserie, this McDonald's exterior celebrates Alsatian design and the "King of Beer."

Two awe-inspiring globes from the reign of the Sun King hang from the ceiling of France's national library.

Twelve grave-faced marble angels guard the emperor's tomb at Les Invalides.

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

A majestic lion statue guards this Parisian botanical garden, and feeds on an unsettling item.