After almost 1,700 years, archaeologists have discovered an underwater city that may have been sank by a tsunami.

The Roman city was back then called Neapolis and was entirely washed away by a very strong tsunami caused by an earthquake on 21 July in 365 AD. It was the same disaster that led to damages in Alexandria in modern Egypt and the Greek island of Crete.

Stretching over almost 50 acres, archaeologists discovered remains of streets, monuments, numerous tanks that produced garum (a popular fish sauce in ancient Rome and Greece, also known as ‘Rome’s Ketchup’).

Missions to find Neapolis have been going on since 2010 however; the objective was achieved after seven years because of favorable weather conditions. The discovery now is more important due to its lack of written records in the Roman literature, because it is thought that the city was being punished for its allegiances, informs Independent.

Mounir Fantar who headed the team said, “It’s a major discovery. This discovery has allowed us to establish with certainty that Neapolis was a major center for the manufacture of garum and salt fish, probably the largest center in the Roman world.”

The city was formerly founded in fifth century BC. Today, the underwater city is right by Nabeuk in the north-east of Tunisia – a popular tourist spot known for its pottery, reported Science Alert.