Experts recovered a number of artefacts from the site
With shafts of sunlight shimmering through a few metres of crystal clear water, you can pick out the cornerstones of an ancient civilisation which inspired literature and legend.
There is more than a whiff of Atlantis about the story of Pavlopetri - the world's oldest submerged town.
But the Bronze Age site, off the coast of Laconia in Greece, has its roots in fact not fiction.
New underwater archaeology techniques - with sonar mapping used by the military and off-shore oil industry - are giving up new secrets.
An international team, given special permission to dive by the Greek government, has found artefacts on the sea bed dating back 5,000 years.
This fresh information puts the world's oldest submerged town well over a millennium older than previously thought.
The new ceramic finds form a complete and exceptional corpus of pottery
Dr Chrysanthi Gallou
Dr Jon Henderson led a team from the University of Nottingham and said the expedition surpassed all expectations.
"This site is unique in that we have almost the complete town plan, the main streets and domestic buildings, courtyards, rock-cut tombs and what appear to be religious buildings, clearly visible on the seabed.
"Equally as a harbour settlement, the study of the archaeological material we have recovered will be extremely important in terms of revealing how maritime trade was conducted and managed in the Bronze Age."
One of the most important discoveries has been what is believed to be a large rectangular great hall, known as a "Megaron", from the early Bronze Age period.
They have also found more than 9,000sq m of new buildings, including a pillar crypt, which could be the first example ever discovered on the Greek mainland.
The Hellenic Ministry of Culture's Ephorate of Underwater Antiquities is overseeing the work.
Official Elias Spondylis said: "It is a rare find and it is significant because, as a submerged site, it was never re-occupied and therefore represents a frozen moment of the past.
The team had a warm reception from local people, who were excited about the project and sense an important part of Greek history and culture would soon be returned to them.
The Mayor of Neopolis, Pavlopetri's nearest neighbour, Jannis Kousoulis, has become one the dive team's most enthusiastic supporters. He hoped the new work will raise the whole region's profile as a place for culture and tourism.
Archaeological co-ordinator for the Pavlopetri project is Dr Chrysanthi Gallou, a post-doctoral research fellow at The University of Nottingham and an expert in Aegean Prehistory.
The investigation offers a great opportunity for [the local community] to be actively involved in the preservation and management of the site
Dr Chrysanthi Gallou
Dr Gallou said: "The new ceramic finds form a complete and exceptional corpus of pottery covering all sub-phases from the Final Neolithic period (mid 4th millennium BC) to the end of the Late Bronze Age (1100 BC).
"In addition, the interest from the local community in Laconia has been fantastic.
"The investigation at Pavlopetri offers a great opportunity for them to be actively involved in the preservation and management of the site, and subsequently for the cultural and touristic development of the wider region."
The team has also been joined by Dr Nicholas Flemming, a marine geo-archaeologist from the Institute of Oceanography at the University of Southampton.
He discovered the site in 1967 and returned the following year with a team from Cambridge University to carry out the first ever survey of the submerged town.
Using just snorkels and tape measures they produced a detailed plan of the prehistoric town which consisted of at least 15 separate buildings, courtyards, streets, two chamber tombs and at least 37 graves. Despite the potential international importance of Pavlopetri no further work was carried out at the site until this year.
The Pavlopetri Underwater Archaeology Project 2009 is at the start of a five-year study of the site which aims to define the history and development of Pavlopetri.
Four more fieldwork seasons are planned before their research is published in full in 2014.
The team is being led by Dr Jon Henderson, from The University of Nottingham
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