These ruins are all that remain of what a Spanish barrack that likely housed a quarry overseer, masons, and stone cutters involved in the construction of the Castillo de San Marco.

The site of Martin Luther King Jr.'s arrest as he attempted to have lunch.

St. Augustine's record-setting narrow street was designed to protect against pirates.

The walls of America's oldest masonry fort famously "swallowed" cannonballs.

Intertwined, interspecies trees which locals believe can grant boons to lovers.

A luxurious 1880s hotel with its fair share of Tiffany stained glass, Edison electricity, and of course, ghosts.

This kitschy curio wonderland is full of fake animals, teak tables, and a cacophony of random bric-a-brac.

Only through the lens of a microscope can visitors see the true treasures inside this museum.

An 18th-century Spanish watchtower made entirely of seashell and concrete.

This bustling Italian plaza is built on the ruins of an ancient Roman amphitheater.

Stare out over the lagoon and beyond from this 10th-century campanile on the island where the city of Venice began.

This amazingly preserved Doric temple was abandoned before it was ever completed.

Cave shrine on Monte Pellegrino.

Fortified medieval tower house with lovely roof garden.

This Roman statue is missing a limb from when the Venetians stole it from Constantinople during the Crusades.

Its interior is adorned with some of the best examples of early Christian mosaics.

A copy of the famous statue can be found in this Florence piazza, along with one of the most breathtaking views of the city below.

Behind medieval walls in a corner of bustling Palermo is a breathtaking former mosque once inhabited by a wolf-taming hermit.

In a city that boasts four separate inclined cable railways, this is one of the busiest funicular lines in the world.

Italian poet Dante Alighieri is entombed in this small mausoleum in Ravenna, and his hometown of Florence has never been too happy about it.

Two stone columns flank the grand Venice square, but there were supposed to be three.

A popular legend claims that the famous pizza was invented at a restaurant in this alley.

A volcanic old faithful, Stromboli has been erupting continuously for the last 2000 years.

One of the world's oldest working clocks is curiously missing the Zodiac sign of Libra.