A large grotto built in the 16th century amidst Florence's famous Boboli gardens.

The only museum with its curator—and her pets—buried inside.

This spectacular bridge is part of an abandoned train line that once connected Mallorcan capital to the southeastern coast.

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

A contemporary art installation housed within a Gothic cathedral.

The iconic boulevard is the perfect place to catch sight of a bicycling skeleton, a levitating Satan, or a chef with his head stuck in a pizza.

Holy Grotto of Montserrat Monastery holds one of Europe's mysterious black Madonnas.

Giant eggs, walls of bread, and nightmare surreality mark the largest collection of works by Salvador Dalí.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

A collection of weird and wonderful art fills a former houseplant nursery.

Charnel house at the foot of Mount Sinai.

The deadliest diving spot in the world is also a stunning geological marvel.

One of its engravings is believed to be among the first representations of medical and surgical instruments.

These Egyptian statues have survived for 3,400 years and were an acoustic wonder of the ancient world.

This ancient structure is widely thought to be the oldest intact pyramid in the world.

Ozymandias’ time-keeping temple.

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

Abstract monuments express sorrow and resilience at the site of a horrific massacre in Nazi-occupied Serbia.

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

A pair of connected skyscrapers form this symbolic gateway.

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

Structure built from the skulls of vanquished foes.

This ancient theater was once the home of fierce gladiatorial battles.

A 16th-century fountain marks the site of a lost medieval cemetery once filled with mass graves.