A bronze statue of the famed Prussian naturalist commemorates the year he spent in Mexico.

In Coyoacán, a pair of coyotes crown a public fountain in reference to the ancient Aztec name of the borough.

This ancient structure was built by a mysterious civilization that was largely destroyed by a volcanic eruption.

These spectacular, symbolic serpents lie within the shadow of the Great Temple.

The ruins of an ancient temple to the Aztec wind god discovered in the middle of a metro station.

These haunting ruins of a 700-year-old Prehispanic city have witnessed centuries of wars and massacres.

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

The meaning behind this triumphal Roman arch was a mystery until the early 20th century.

Believed to be the remains of the lost Temple of Minerva, this nymphaeum has been known by its misnomer to this day.

The remains of this 2nd-century Roman temple are incorporated into a modern building.

An ancient Roman temple first dedicated to an emperor's wife is now a church.

This one-of-a-kind Roman arch is not actually dedicated to the god Janus.

One of Catholicism's four major basilicas has a series of papal portraits that are said to predict the end of the world.

This small, ancient Roman temple was once a church dedicated to the patron saint of penitents.

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

Ancient ruins hidden underneath a modern luxury hotel.

Brass cobblestones mark the places where individual Holocaust victims were taken from their homes.

More sculpture than building, this architecturally significant temple was built on the spot of Saint Peter's crucifixion.

This ritzy Italian market is built around a statue of an unforgiven heretic who was burned for his belief in an endless universe.

An imperial fortress city that incorporated cultural elements from the entire Mughal empire, only to be abandoned the year it was finished.

This beautiful 16th-century necropolis marks an astonishing feat in heritage conservation.

An unassuming tomb houses an important milestone in Indian architectural history.

An ancient iron pillar in Delhi that seems to be rustproof.

Also known as the "Red Taj Mahal."