This gallery commissioned by Cardinal Spada is known for its magnificent optical illusion.

The sacristy of this church contains remains and relics of members of the Aragonese royal family.

What appears to be an ancient Roman temple is actually a Catholic church.

This hydrochronometer was invented by a Dominican monk and is a prime feature in this garden.

This medieval church in Rome was almost destroyed following a terrorist attack in 1993.

Next to the Leaning Tower of Pisa is a cemetery home to ancient sarcophagi and disturbing murals.

A secluded, little-known temple hidden amid the dense jungle.

Formerly known as Saville Theatre, this mid-20th-century entertainment hub includes an ornate frieze.

Underneath this Byzantinian church lies a necropolis filled with ancient tombs and the ruins of previous churches.

Constructed on the ruins of a convent, this tower saved countless lives.

Stuck in the arcade of Casa Isolani are three arrows of mysterious origins.

A large replica of a monumental Roman inscription is located on the side of this museum.

The intricate geometry inside this Baroque-style dome was designed to create "terror of the human soul."

A 15th-century monumental Latin inscription on this house celebrates Lorenzo Manilio's love for Rome.

The roof of one of the world’s largest spice markets provides a grand view over the neighborhood's glorious bustle.

A large statue of Pope Gregory XIII in Bologna was disguised as Saint Petronius to avoid destruction.

The Italian revolutionary's legendary wife is portrayed on horseback waving a gun and holding her child in this memorial on the Janiculum.

A brutalist gem towering over the heart of Milan.

For decades, vendors have sold clothes once worn by American soldiers who stormed Italy in the 1940s.

This Roman arena once played host to bloody gladiatorial battles.

The smaller of the three towers of San Marino is a former prison inaccessible from the ground level.

It took more than 300 years to build this church, which is home to two sacred vessels believed to hold the blood of Christ.

A room filled with frescos that make it seem like the walls are crumbling down while giants die in despair.

This church is named for one of the most dramatic tales in the early Christian church.