After completing more than 200 dives over a period of 18 days, he said the group were "euphoric" at the find, and called for a fuller investigation of the site.

However, Bolivian archaeologist Dr Carlos Ponce is skeptical about the real significance of the find, and says the expedition has yet to provide any concrete proof.

He points to 12 previous expeditions in Lake Titcaca, including one by French explorer Jack Cousteau in 1968 in a submarine - which revealed nothing.

Superstition

Local communities, some of whom are very superstitious, regard the expeditions with suspicion, fearing they will only bring bad luck.

Archaeologists say they have evidence of a major find

"We think it's a bad sign, and maybe in the future there will be some accidents because people didn't respect the lake", warns Javier Crespi, from Copacabana, one of the towns bordering Lake Titicaca.

However the possible discovery of the underwater remains of a 1,000-year old civilization only adds to the aura of legend and mystery which surrounds Lake Titicaca, and is likely to attract more and more sightseers to what is already Bolivia's prime tourist attraction.