Exploring The Sunken Roman City of Baia in Italy

The city of Baia was a center of hedonism for the Roman elite. Much like Las Vegas, Baia catered to the desires of the rich and powerful. The debauchery didn’t last as the Saracens sacked the century in the 8th century. By 1500, the last remaining residents left. Today, you can find a large part of the sunken city of Baia submerged in the bay of Naples. 

Some consider the sunken city of Baia to be the  "Las Vegas" of the Roman Empire
Some consider the sunken city of Baia to be the “Las Vegas” of the Roman Empire

The History of Baia

The town sits on the Gulf of Naples’ northwest shore. It’s believed to be named after Baius, one of Odysseus’ crew in Homer’s Odyssey.

The town sits on the Phlegraean Fields, which is known for heavy volcanic activity. This volcanic activity made the location perfect for the hot springs that would make the town famous. 

Some think the builders intended Baia to be a port for Cumae, but it was a popular resort for the elite by the end of the Republic. Pompey, Lucullus, and Pompey were frequent guests during the Republic. Julius Caesar had his own villa there.

During the Empire, Augustus bought much of the town. Nero built a massive villa in the 1st century CE, and Hadrian actually died there in 134 CE.

One story revolving around Baia that has become legendary to many involves Caligula. In Gaius Suetonius Tranquillus’ The Twelve Caesars, he described how Caligula built a three-mile-long pontoon bridge from Baia to Puteoli and rode a horse across the bridge while wearing a gold cloak. Tranquillius’ account is highly critical of this stunt due to his hatred of Caligula, so you should take some of the details with a grain of salt.  

During the Roman Empire, the city began to sink into the ocean. The slow sink into the sea drove many residents away. More people fled when Muslim raiders sacked the city in the 8th century and the remaining people fled around 1500 when a malaria outbreak devastated the town.

How Did It Sink Into The Ocean?

The Phlegraean Fields that Baia sits on is a collapsed caldera with a large amount of seismic and volcanic activity. As the magma underground chambers fill and empty, the ground descends in a process called bradyseism. 

Between the 3rd and 5th century CE, Baia began to sink into the ocean. By the time it was sacked in the 8th century, the lower part of the city was completely submerged in the sea. Currently, 328 feet of the site sits in the bay.   

Baia Today

Today, Baia is a great tourist destination and one of the only places you can see an underwater city. You can see it by scuba diving, snorkeling, or even through glass-bottom boats.

under water statue in sunken Baia
Statue in the Sunken part of Baia

This experience doesn’t even include what’s above water. If you don’t want to get into the water, you can explore some amazingly well-preserved Roman ruins. 

Before the Pantheon in Rome in 128 CE, The Temple of Mercury was famous for having the world’s largest dome. This miraculous piece of engineering was 71 ft in diameter. The temple itself held the cold swimming pools of the cities public baths.

The Temple of Mercury
Inside the Temple of Mercury
The 71ft dome of the Temple of Mercury
The 71ft dome of the Temple of Mercury

The Temple of Diana was another impressive architectural feat, though it is half-collapsed today. Romans designed the structure to capture vapor from the thermal baths it held.

The Temple of Diana
The Temple of Diana

Deep underwater, you can find a nymphaeum built by Emperor Claudius. If you’re unfamiliar, a nymphaeum was a monument consecrated to nymphs, which Romans believed were minor gods. You can see the many sculptures that populated, along with others found, in Baia’s museum.

Mosaic in the Sunken city of Baia
Mosaic in the Sunken city of Baia

The Temple of Venus gets its name from the 16th-century Neapolitan historian and writer Scipione Mazzella, who claims he discovered a statue of Venus there. This octagonal building is missing some of its walls and its roof.

The crumbling Temple of Venus
The crumbling Temple of Venus

You can find the remnants of the private and public bathhouses that made the now sunken city of Baia famous throughout the area. A complex system of chambers and channels created by Roman engineers funneled warm water from hot springs into these saunas. Romans used baths for relaxation and medical purposes, stemming from the physician Asclepiades, who recommended warm and cold baths to remedy illness.

Mosaic in the bathhouse of the Temple of Venus

High up looking over the sea is the Villa of Ambulatio, which consists of six gardens connected by staircases. Most of the structures are gone, but some rich and powerful Romans likely lived in this area.

The Villa of Ambulatio – Ra Boe / Wikipedia

The Sector of Sosandra is an exciting area because we don’t know how Romans used it. Like the Villa of Ambulatio, it’s a series of interconnected terraces that held a spa, hotel, or a villa. Some even believed that it was a meeting place for Nero and the nearby Miseno fleet.

If you’re ever in Italy, the sunken city of Baia would be a fantastic place to visit. Time didn’t preserve the structures as well as Pompeii, but there’s something novel about an underwater city, especially when it’s full of such exciting history.

Alan Behrens

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