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

The scorched Lisbon church that survived two earthquakes and a massive fire.

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

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

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

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.

Hundreds of caves once used to store grains and animal feed.

Memorial to the brave indigenous defenders of the Canary Islands.

Two sections of the old dam that made it possible to tame the Meuse in Belgium in the 19th century.

The world’s largest museum dedicated to mining, complete with an underground show cave.

This 165-foot water tower has been supplying the residents of Varel with drinking water for more than a century.

Once the longest swing bridge in Europe.

Nobody knows what this saucer-like ancient Egyptian object was for.

A preserved oasis with traditional Andalusian-style architecture and beautiful views of the Nile.

Slum Settlement Filled With Mountains of Garbage.

The medieval center of the Islamic world was also once the seat of Saladin's sultanate.

Standing atop 2nd-century Roman ruins, this church is one of the oldest and most iconic in Old Cairo.

In Egypt's expanding metro area, many of the neighbors are dead.

One of Malta’s most important Neolithic sites sits in a suburban area south of the country’s capital.

Engineering ingenuity during the battle of Gibraltar.

A curious memorial to the Berlin Wall, German division, the war, and those who died at the wall.

One of the world’s only museums dedicated to the humble matchstick.

One of the smallest bookstores on the planet.