The Altamira Cave in northern Spain, declared a World Heritage Site by UNESCO, is to re-open to the public.
The cave whose walls are covered with paintings that include abstract shapes and animal subjects over a length of more than 270 metres was discovered in 1868.
It was inhabited approximately 35,000 to 13,000 years ago.
The cave located at Santillana del Mar, in the Cantabria region, was closed in 2002 after damages had been reported to its polychrome prehistoric paintings from the carbon dioxide in the breath of the large number of visitors.
Around 192 visitors would be allowed in under the programme and they will have to comply with a strict dress code and wear special suits, masks and shoes.
In January the foundation which manages the cave said it could reopen to groups of five people a week, because of the spread of micro-organisms due to human visitors and for 37 minutes.
The impact of the visits on the paintings will be reassessed in August.