This small city where almost everyone lives in the same building can only be reached via North America's longest tunnel.

Running under an entire mountain, the longest highway tunnel in North America is kept fresh using portal fans and jet fans.

This WWII-era military installation once held an entire city within its walls - now, its walls are falling down.

This tribute to a local man towers within a quaint lakeside park.

Perhaps the most spectacular grotto along the Algarve coastline.

This museum collects over a century of automobile history including the iconic car from The Muppet Movie.

A 16th century chapel decorated with bones, skulls, and entire bodies hanging from the wall.

"Portugal's Stonehenge" is made up of nut-like stones aligned with the heavens.

This star-shaped military outpost is now simply trying to protect itself from neglect.

This castle has links to Portugal’s founding and struggles for independence.

A stunning 18th-century site where pilgrims ascend by a series of punishing stairs only to return via funicular.

Elaborate tile work in this railway station tells the story of Portugal.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

A hidden three-foot-wide house separates these two regal churches.

One of the largest Roman settlements in Portugal.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

This unreal Portuguese palace looks as though it's made from a pile of different castles.

A deer-headed statue that brings together a 12th-century legend and big wave surfing.

The corpse bride of Portugal.

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

An exquisite collection of fairytale conveyances that puts most car museums to shame.

The granddaddy of all tourist traps, built on ice water, jackalopes, and a giant dinosaur.

A place to eat for on-the-run agents and espionage enthusiasts.

Every St. Andrews student knows to avoid this inscription for fear of a martyr's curse.