What is being billed as the world's largest Stone Age art gallery will soon open to the public in Portugal. Prime Minister Antonio Guterres is expected to open the first visitor reception centre at Cocirca Valley Natural Park on July 28. The gallery, near Vila Nova de Foz Cocirca in eastern Portugal, features hundreds of ancient outdoor engravings of prehistoric animals. Julio Meirinhos, a lawyer appointed to develop the park, said: 'It is of world importance, probably the biggest open-air palaeolithic site in the world.' A world-wide campaign to save the engravings was launched after they came to public attention during the construction of a US$300 million reservoir in the valley. The Portuguese Government was eventually persuaded to abandon the half- built dam in favour of the park. 'The power of money crumbled before world cultural interest,' Mr Meirinhos said. He applauded the Government for the 'intelligence of its decision'. The engravings, depicting Ice Age oxen, deer, horses, bulls and cows, are etched along 19 kilometres of the remote River Cocirca valley. They were previously known - but only to shepherds who had neither appreciated they were so old nor that they were so rare. Only when construction by the state electricity company, Electricidade de Portugal,of the dam got under way did an archaeological study determine the age and cultural value of the engravings. An initial proposal to chisel the paintings from the rock and preserve them elsewhere was ruled out because they were engraved on shale, which shatters easily. Banker John Crisostomo, who had been campaigning against the building of the dam said: 'It's a unique record of the world 20,000 years ago. It had to be preserved at all costs.' Now a development programme, partly funded by the European Union, has been drawn up for the valley. The valley is poised to be a major tourist attraction. A dozen new roads are being built, plus an information centre for visitors and a scientific study institute. Enterprising locals are being encouraged through grants to provide tourist accommodation, which is in short supply. Some locals are already capitalising on the find. Guides have been hired to lead tourists down the steep valley on escorted tours, while a local beverage, labelled 'Prehistoric Wine', is already on sale in nearby towns.