A three-story tower of books about Abraham Lincoln is one of the more unusual monuments to the president.

The winding route passes through an enclosed alleyway, two tunnels, and leads to the White House basement.

A derelict bit of transportation infrastructure hidden in the woods.

A historic neighborhood church is reborn as a psychedelic arts collective.

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

One of the most photographed buildings in a city known for its Modernista architecture is an abandoned squat.

This colorful statue welcomes visitors to a Barcelona park.

One of Antoni Gaudí's least-visited works, an homage to Catalan patrimony that mixes neo-Gothic with Modernista forms.

Occupied for six centuries by Franciscan Order nuns, this monastery is an amazing ode to Catalán Gothic architecture.

The oldest giants in Catalonia are now displayed in a 14th-century Gothic church.

A former steam-powered mill from the 1800s is now an industrial park with a giant steel dragon slide.

Gaze upon chocolate sculptures depicting everything from chariot races to Gaudí's famous church at this shrine to sweets.

Mountain where Jesus was first tempted by the Devil.

Step inside the first house designed by Catalan architect Antoni Gaudí, considered to be one of the first Art Nouveau buildings.

An unusual stroll through gentlemen's erotica demonstrates that pornography is timeless.

Tucked away inside this concrete building is a church and its grand display of brutalist architecture.

This oddly shaped church resembles a rocket.

Building owners can take out tiles for free at this repository for historic building materials.

A small but charming botanical garden that contains many exotic plant species.

This architectural beauty is the home to a personal collection of more than 600 examples of mechanical musical instruments.

One man's remarkable private collection of art from around the world.

One of the few places in Portugal where the Celtic ritual of wearing large wooden masks is still practiced.

Europe's largest collection of matchbox designs is a fascinating exploration of the cultural history of the world.

This giant sculpture made of trash is a critique of society's wastefulness.