Over time, this castle grew to encompass the entire island.

These magnificent city walls rise from the barren sun-baked Spanish plains like something straight out of a fairytale.

This spaceship-like Serbian monument reaches for the stars in celebration of the fallen fighters of fascism.

This feat of Brutalist architecture is also known as the Three Sisters.

A pair of connected skyscrapers form this symbolic gateway.

Gargantuan home of Russian science.

The tallest hotel in Europe.

The oldest continuously occupied public building in the United States.

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

Ancient cliffs resembling a kilt on Scotland’s second-largest island emit an entrancing sound.

A tragic legacy of the attempt to beautify Skopje and line the pockets of corrupt politicians

These abundant, over-the-top monuments are so widely scattered that they define the entire compact capital cityscape, often leading to jokes about whether there are more statues than residents.

A Brutalist architectural gem hidden among Skopje’s neoclassical buildings.

This fortress dates back to the 6th century and is also the site of a controversial abandoned restoration project.

Space-age monument to an early 20th-century uprising.

This historic folk museum celebrates the attention to detail that makes America great.

A memorial dedicated to the victims of the Columbine High School shootings.

This swanky speakeasy is Denver’s oldest bar—and hasn’t changed a bit since 1933.

Take a self-guided tour through one of Colorado's most elevated mining districts.

This natural spring is the winter home to the largest gathering of manatees in the world.

Where the famed daredevil attempted to launch himself across a canyon in a custom-built rocket.

An exhibit of items from the mental institution where Mary Todd Lincoln lived after her son conspired to have her committed.

Soldiers were buried next to Lee's house in the center of Arlington Cemetery to dissuade the general from reclaiming his property after the war.

A unique arch graces the Dolores River Canyon near the Hanging Flume.