A neo-Gothic mansion now houses a wunderkammer of analog tech that hits on all the senses.

A whimsical village of unique treehouses resides in a Washington forest.

The Netherlands is home to a bridge printed out of reinforced concrete.

The stunning interior of this Gothic church is covered in ornate gold details.

The site of London's first coffee house has been serving refreshments of one kind or another for 360 years.

Hidden beneath the streets of London is a secret subway that only carried mail.

Home to Alan Turing, the cracking of the Enigma code, and Captain Ridley's shooting party.

Crawl through the hole in the middle of this stone to break off a bad relationship or initiate a good one.

A meow-velous tribute to a beloved street cat, made famous on the internet.

This former charity hospital for elderly clergy houses some of Seville’s most treasured paintings.

Puffin enthusiasts flock to Europe's largest seabird cliff, which over one million birds call home.

Mysterious face-like images that appeared within an Andalusian house are surrounded by legends of the paranormal.

A stunning hermit's shrine on a steep rocky spur in Northern Italy.

These ancient sunken lanes were naturally tunneled into the soft ground by countless footsteps.

Mirrored floors and arched shelves create the illusion of an infinite tunnel of books.

A visionary Italian architect created an impressive cluster of concrete structures for a family's private tomb.

There's a piece of New York City transportation history hidden in plain sight at a Manhattan subway stop.

An exact replica of a colossal Olmec head sits atop a pyramid within a Madrid traffic circle.

A small granite monument marks where the borders of three countries meet.

A vintage video game wonderland in downtown Reykjavik.

The martyr's wax-enhanced skeletal remains lie preserved in a glass case in the Santa Maria della Vittoria in Rome.

At just 25 inches at its narrowest point, it's one of the tightest streets in the world.

The unedited photograph called "Bliss" has graced the screens of over a billion computers.

This nearly invisible wire transforms much of the city into one big, symbolic home on the holy day.