The paintings are said to be in excellent condition
Scientists in Australia say a chance discovery by a hiker has become one of the most significant finds of Aboriginal rock art in the country's history.
The rock paintings - which are up to 4,000 years old - were found by a hiker who stumbled upon them in a cave in a national park near Sydney in 1995.
The inaccessibility of the area has kept researchers from conducting a full-scale investigation of the find until May.
New South Wales's Premier Bob Carr said the "remarkable" discovery confirmed the richness of Aboriginal culture and spiritual life.
It's like an ancient world that time forgot
Anthropologist Paul Tacon
"This reminds us 4,000 years ago, when you had civilisation
flourishing in Mesopotamia, when you had the power of Egypt, before
China was united, while Stonehenge was being built, we had
Aboriginal people in these lands, on the outskirts of the Sydney
basin," he said.
The cave's location in Wollemi National Park near Sydney has been kept secret to avoid damage by vandals or well-meaning sightseers.
The cave - 12 metres (40 feet) long, six metres deep and one to two metres high - holds 203 paintings, stencils and drawings in excellent condition.
They show humans and god-like human and animal composites, such as birds, lizards and marsupials - including an extremely rare depiction of a wombat.
"It's like an ancient world that time forgot," said Paul Tacon of the Australian Museum, who led the expedition.
"We've never seen anything quite like this combination of rare
representations in so many layers," he said.
"The superimposed layers in various colours such as red, yellow, white and charcoal black are in pristine condition."
Local Aboriginal representative Dave Pross said the art gave a picture of local tribes' rituals and needed to be studied more.
"It shows our traditional practices, where we were. We're just trying to get the history of it and look after it," said Mr Pross.