Archaeologists have discovered what they describe as a previously unknown ancient civilisation in Central America.
By Richard Black
BBC science correspondent
The site, near the Atlantic coast of Nicaragua, dates from before the Mayan era, and relics include what appears to be a centre for mass production of ceremonial columns.
A picture has emerged after several years' research
Researchers have been working on the site at El Cascal de Flor de Pino, near the town of Kukra Hill for six years.
They've found evidence of an ancient town and several outlying villages, which developed around 2,700 years ago and lasted for a thousand years.
There are monuments, petroglyphs (rock carvings) and pottery, and most remarkably, an area where many huge columns were formed out of rock - columns which may have been used at burial sites.
"The pottery is similar to pre-classical pottery found at sites of similar age in Belize," Dr Ermengol Gassiot, of the Universitat Autonoma de Barcelona, Spain, told BBC News Online.
Petroglyphs are abundant
"And the columns resemble those found at Mexican sites where they had ritual uses.
"The society had political centres. Kukra Hill, we believe, was a small town, and at least three villages lay around it and were dependent on it."
The newly discovered civilisation is similar to the societies that preceded the Mayan civilisation further to the north.
Independent experts say this shows that the process that led to the founding of the Mayan cities, such as Tikal, Palenque, or Copan (in Guatemala, Mexico, and Honduras respectively) covered a much larger geographical region than archaeologists have supposed up to now.
A centre for mass production of ceremonial columns
Much research remains to be done at El Cascal de Flor de Pino but it promises to reveal a vast amount about the various societies and customs which were eventually assimilated into the great culture of the Mayas.
Commenting on the discovery, Jeremy Sabloff, Williams Director of the University of Pennsylvania Museum of Archaeology and Anthropology, US, said: "This site sounds very exciting and full of potential.
"We're learning lots now about the pre-classical era - the groups which came before the Maya - and this discovery greatly extends the range of these pre-classical civilisations."
New information about pre-classical times
In addition to researchers from the Universitat Autònoma de Barcelona (UAB), the Kukra Hill archaeological team includes members from the Universidad Nacional Autónoma de Nicaragua (UNAN-Managua), and the Consejo Superior de Investigaciones Científicas (CSIC).