He moves with steady silent purpose. The cold gravel scrunches begrudgingly beneath bare feet. The cave wall is chipped and hard. The icy air moves in just a whisper of a draft. In the distance he can hear the drip of water trickling to a subterranean lake. It drains into a silent black river that moves snakelike through the darkness.

He stops. He can feel the defined outlines left by the hands of others who have come before, some of them thousands of years ago. He drops to his knee by an old fire pit and shapes the kindling he has brought into a small pile. Friction sparks smoke into flame. Light bursts on a mural of creatures etched into the rock. Symbolic. Historic. Moments of past hunts, future dreams.

Using his stone tool, he starts to draw, expertly cutting his image into the smooth plane of the rock. The lines are bold, defined, proportioned. The head is small, the eye expressive, the mane thick, the belly large, the legs narrow and tapering. The horse emerges to join more than a hundred other creatures roaming the wall - bison, aurochs, ibex, chamois, cats, deer, seals, auks and fish.

As he leaves, he impresses the painted imprint of his hand on the wall. His signature. His place in a time that was timeless beyond the rhythms of sun and moon and the passage of seasons. His work is done. He has left his mark. And he has no idea that 20,000 years into the future others would come and marvel at the exquisite beauty of his equine art.

In 1985 professional deep-sea diver Henri Cosquer discovered a narrow cave entrance nearly 40 metres below sea level on Cape Morgiou, near Marseilles, on France's south coast. Following intuition, he swam over 130 metres along a sloping tunnel to a large air-filled chamber. What he saw took his breath away and he returned with other explorers to document the paleolithic cave art that had been etched and painted on the walls during a period between 19,000 and 27,000 years ago.

Of the one hundred images of animals in Grotto Cosquer, horses constitute nearly one-third of the total. Some pictures are of single heads, others are of the whole animal. Some are in herds. Some are alone. In one image even the colour of the coat is obvious. Prehistoric rock art is one of the most exciting and intriguing legacies of our distant ancestors. It is a worldwide phenomenon spanning almost every continent with artistic design from a simple wavy line to details of animals in action. It is found from the tropics to the Arctic, from deep caves to the tops of mountains. Evidence of the simplest forms of sculpture have been dated to 250-300,000 years ago in eastern Europe while Australian and African rock art date back to at least 60,000 and 50,000 years respectively.