Just across from the "Last Supper" painting is the famous painter's vineyard, a gift received for creating the masterpiece.

An ossuary built in 1210 to collect bones from the Ospedale Maggiore of Milan.

These abandoned country fairgrounds are filled with replicas of Spanish monuments.

Just like in Hollywood, Madrid has also a forgotten walk of fame.

The little church's beautifully frescoed ceiling has earned it the nickname “the Sistine Chapel of Madrid.”

A stone slab in Madrid marks the point from which the distances of Spain's national roads are measured.

A psychedelic labyrinth on the San Francisco bay.

A modern mechanical planetary system, part of a 10,000 year clock.

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

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

A huge musical instrument played by the ocean.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

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.

The world’s oldest and biggest bookstore stocking only mystery, crime fiction, espionage, and thrillers.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

This beautiful building in the heart of Manhattan's Financial District was empty for decades.

The artist James Turrell is repurposing an extinct volcano crater as an observatory to experience the cosmos.

An abandoned facility that has become a place of ritualistic satanic worship, or so rumor has it.

A mysterious "wedding cake" castle in the middle of the urban desert.

This striking public art installation is suspended above a public park, designed to gently move in the breeze.

A self-built castle made by a mysterious man.

Artist James Turrell's ode to dawn and dusk on the campus of Rice University.

A park filled with vibrant mosaics created by more than 300 folk artists.