Wolfe Creek Crater, Western Australia.

To venture outback is to take a giant step back in time, writes Bruce Elder.

Wolfe Creek Crater, Western Australia

No one knows exactly when a meteorite hit Western Australia and made this crater, 1,900 kilometres north-east of Perth near Halls Creek. The best estimates are that it was about 300,000 years ago and had a mass of about 50 tonnes. The crater was probably 120 metres deep after impact.

Today, there is only 60 metres between the edge and the bottom. At 880 metres across, it is considered the second largest crater in the world, behind the Arizona meteor crater. From the distance it appears as a low hill but when the rim of the crater is reached it is a sight of great symmetry and beauty. See www.naturebase.net. For tours phone Halls Creek Visitor Information Centre, (08) 9168 6262.

Hamelin Pool and the Stromatolites, Shark Bay, Western Australia

At first, the stromatolites seem like nothing more than cauliflower-shaped rocks on the edge of Shark Bay. As you walk around the raised boardwalk, what you are seeing are the end products of microscopic living organisms known as cyanobacteria, which secrete a fine film of mucus. Sediment attaches to this mucus and so these rocks grow, at a rate of about 0.5mm per year. At Hamelin Pool you are watching a process that is being carried out by the oldest known living organisms on earth. Guided tours can be booked through Denham and Monkey Mia Visitor Centre, phone 1300 135 887 or see www.sharkbaywa.com.au.

Ellery Creek Big Hole, near Alice Springs, Northern Territory

Above the waterhole in one of the many gorges cut through the MacDonnell Ranges to the west of Alice Springs is a low cliff face which has been twisted into improbable shapes. This is the remnant of a mountain range that once was higher than the Himalayas. About 350 million years ago heat and pressure pushed rocks, made from the mud and sand of a vast inland sea, so high that the range reached 10,000 metres. All that is left are the very bones of the earth worn jagged and bare by millions of years of erosion. Many tours from Alice Springs include Ellery Creek in their itinerary. See www.centralaustraliantourism.com.

Naracoorte Caves, South Australia

Naracoorte Caves Park is one of only three fossil sites in Australia to be given an official World Heritage listing after the discovery of fossils dating back 170,000 years and ranging from tiny frogs to megafauna. In the state's south-east, it is recognised as one of the richest collections of Pleistocene fossils in the world. Of the four caves open for inspection, the most impressive is the Victoria Fossil Cave where 93 different species of mammals, reptiles, birds and frogs have been found, including bones and fossils of giant kangaroos, large marsupial lions and giant wombats. Naracoorte Caves National Park, phone (08) 8762 2340. For tour information, see www.parks.sa.gov.au.

Lark Quarry, Queensland

This site is the only known record of a dinosaur stampede anywhere on the planet. It was discovered in the 1960s by a local station manager, Glen Seymour, and in 1976-77 a team of palaeontologists moved in and more than 60 tonnes of rock were excavated from the site. Today a conservation building keeps it protected from the searing temperature, the rain and the dust.

Nourlangie Rock, Kakadu National Park, Northern Territory

There are a number of outstanding rock art sites in the World Heritage-listed Kakadu National Park but none is as interesting as the Anbangbang Gallery at Nourlangie Rock south of Jabiru. The point of interest here is the image of Namarrgon the "Lightning Man" and Nabulwinjbulwinj, a dangerous spirit who eats females after striking them with a yam. Namarrgon wears his lightning as a band connecting his arms, legs and head. The stone axes on his knees and elbows make the thunder. Rangers offer guided tours in the dry months. Phone (08) 8938 1120, see www.environment.gov.au/parks/kakadu.

The Quinkans at Laura, Queensland

At Laura, on the road between Cairns and Cooktown, archaeologists have found evidence of an Aboriginal settlement which may be the oldest in Australia. The area is also famous for its giant figures, known as Quinkans. These are spirit figures that usually lived in cracks in the rock and came out to frighten people and to keep them "in line". The Split Rock and Guguyanlangi Art Galleries lie about 10 kilometres south of the town. They are only open to visitors after a formal application to the Aboriginal ranger in Laura, phone (07) 4060 3233. Guided tours can be booked through the Quinkan Cultural Centre, phone (07) 40603457, see www.quinkancc.com.au.

Lake Mungo, NSW

In terms of human history Lake Mungo - a remnant of a lake which has not been filled with water for at least 13,000 years - is one of the transcendental landmarks. It was here, some 25,000 years ago, that Aborigines cremated and buried a young woman. On the 25-kilometre-long sand dune remnant marking the eastern edge of Lake Mungo, the first evidence of human beings attaching an elaborate ritual to death was found. It is also here that archaeologists have found the bones of ancient megafauna including a 15-kilogram Murray cod. Guided tours are essential. Harry Nanya Tours, phone (03) 5027 2076 or see www.harrynanyatours.com.au and www.nationalparks.nsw.gov.au.

Organ Pipes National Park, Keilor, Victoria

Some volcanic formations are genuinely breathtaking. This is certainly the case with the Organ Pipes National Park, on Melbourne's north-western edge, where the visitor, after a pleasant walk down the hill (you have to walk back) can see the million-year-old organ pipes - they are actually hexagonal basalt columns - and further around a tessellated pavement which stretches across a gentle hillside, and the remarkable Rosette Rock, which is in the shape of the spokes of a wheel. This is all part of a lava flow which occurred about 1 million years ago and was, in places, some 70 metres thick. See www.parkweb.vic.gov.au

Huon Pine forests near Strahan, Tasmania

Who can forget, when the environmental movement was trying to save the Franklin River, the image of a young Bob Brown standing next to a huon pine that was going to be bulldozed and pointing out that it had been there since before the birth of Christ. Huon pines, the most beautiful of trees, are one of this country's great living treasures and are really worth seeing in the wild. There is a strict policy about cutting trees down, but you can buy products made from huon pine. The trees are best seen on Tasmania's west coast either by the Teepookana Huon Pine Experience or on a cruise up the Gordon River. See www.forestrytas.com.au; www.discovertasmania.com