A towering spire in the fortress of Kalemegdan honors the victorious armies of Serbia during their struggles against the Ottoman Empire.

Destroyed Serbian army headquarters sits half crumbled in a largely revitalized Belgrade.

A pair of connected skyscrapers form this symbolic gateway.

A Serbian church lit by chandeliers made of weapons.

Nikola Tesla's ashes are held in a golden sphere, surrounded by his works.

A unique seaside cave where Aleister Crowley faked his own death.

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

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

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

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

This restored Portuguese cafe may well be the most beautiful place in the world to grab a Big Mac.

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

Hidden beneath a beautiful overlook you’ll find the history of the city depicted in comic strip format next to a pay toilet.

One of the smallest bookstores on the planet.

Catering to broken dolls for almost 200 years, this repair shop is now a charnel house of doll parts.

The best place in the world to buy tinned fish.

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

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.

The world's oldest bookshop still in operation.

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

Amsterdam's narrowest house facade is a monument to 17th-century tax evasion.

One of Amsterdam's narrowest houses is located right across the canal from its widest.

Museum preserving torture methods from the past.