A marvel of Byzantine engineering under the streets of Istanbul.

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

This ancient Irish tower could easily have stood in for Rapunzel's prison.

Thousands of flamingos and other bird species flourish in these Camargue wetlands.

The lost Latin words were reconstructed using the holes from the nails that once pinned them in place.

This ancient Roman bridge and aqueduct still stands as a wonder of classical construction.

The mental institution where Van Gogh created some of his most famous work now allows guests to walk in the artist's footsteps.

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

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

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

Eat the ultimate iteration of Portugal's most beloved pastry.

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

An ancient and majestic fortress that played an integral role in Portugal's road to independence.

This enormous censer uses a pulley system installed over 400 years ago.

The oldest operating roller coaster of its kind, the Montaña Suiza has been thrilling riders since 1928.

Giant topiary dog once played a role in a terrorist bomb plot.

This 18th-century pond is one of the main attractions in the Jardín del Príncipe in Aranjuez.

A towering monument in Spain has proven to be more labor-intensive than initially planned.

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

This macabre masterpiece of a mural is one of Francisco Goya's "Black Paintings."

A lush indoor jungle fills this bustling Madrid transportation hub.

A haven for book enthusiasts across the street from Retiro Park.

A must for film lovers in Madrid and home to the Spanish Film Library's projection space.