From Mount Diablo, thousands of hectares of unpopulated land stretch as far as the eye can see. It was from here that the Wild West was first surveyed by the early settlers. Even today, America's vast and thinly inhabited Mid West beckons modern pioneers. 'The frontier means hope, where the rules haven't been written yet, where you haven't been defined yet' explains one sociologist. 'The pioneer spirit is in our blood,' agrees Patricia Limerick.

Across the US, monuments to the Founding Fathers are almost worshipped by an adoring people. Canons fire from a galleon as a troop of blue-coat soldiers file ashore. It's a reconstruction, championing the pioneer spirit which made America what it is today.

And the 'Wild West' is still being colonised. But now untamed land and ranches are replaced by new developments in the Mojave desert. Las Vegas, the modern equivalent of the gold and silver mines of 100 years ago, is growing by over 1000 new inhabitants a week. 'Americans are told they need the family home to live the Jeffersonian ideal. By nature Americans have to have wide-open spaces,' explains sociologist Mike Davis. This pioneering spirit means that the US has one of the highest home ownership rates in the world.

Whether it's their homes, TVs or cars, more space equals more freedom. Typical American, Stephanie Prather talks fondly about her walk in closet, huge refrigerator and 41 inch t.v. "By my friend's standards that's small," she explains. To her, they are 'the one space on the entire planet that's mine. I can do what I want, when I want, how I want.' Huge, inefficient SUVs and even the size of Americans themselves are the ultimate example of how, in American eyes, size equals control.

This American pioneering spirit is also seen in its expansion around the world. 'We still have the courage and tenacity of 100 years ago' states Patricia Limerick. 'What other country can attempt to instil the love of democracy and the actuality of regular government in a country the size of Iraq?

And it will most likely continue on. 'They're absolutely fascinated with the idea they must assume a dominant place in space. They talk about the ultimate imperial base - controlling the entire earth, from weapons in space aimed back at earth,' proffers Johnson. Robert Zubrin has plans to colonise Mars. 'Mars calls with an open book, a history book filled with blank pages,' he tells us. He has already built two Mars simulation centres, in the Arctic and American desert.

The 'pioneer spirit' of Lewis and Clark is key to American history and to its present. How much longer America can continue expanding remains to be seen.