From the early days of the industrial revolution until the industrial repression of the Eighties, the men of Doncaster tramped over the River Don and were lowered into dark tunnels to mine coal. The coal was fed into the fireboxes of the magnificent steam locomotives - Sir Nigel Gresley's "Mallard" and "The Flying Scotsman" among them - that were designed and built at Doncaster
Until the Eighties, Doncaster was a place of industrial might and trade union power. And the surrounding countryside, in-cluding the romantic Don Valley, had long been an area of ash pits and slag heaps. Coal and heavy industry kept home fires burning and drove "Mallard" up to 126mph, a world record for steam. It also gave miners emphysema and blasted the landscape.
The Thatcher revolution has given Doncaster a superstore and leisure park where shamefaced grown men dressed in Casey Jones-style dungarees and neckerchiefs drive miniature electric trains in the guise of old-time American steam engines. Not more than 10 years ago, they would have been making full-sized railway equipment for British Rail. In the vast new multiplex cinema, teenage lads shovel popcorn into voluminous plastic tubs; a few years ago they would have been digging coal from seams several thousand feet underground, and in their grandfathers' day shovelling several tons a day into the hungry furnaces of "Mallard" and "The Flying Scotsman" as they raced between Edinburgh and King's Cross.
How does the Earth Centre, fruit of the ecology movement, fit into this picture of post-industrial Doncaster? The answer is, remarkably well. The Earth Centre was dreamt up by Jonathan Smales, a former director of Greenpeace, from the bedroom of a tiny flat in east London and founded five years ago.
Mr Smales wanted to create an environmental centre - part didactic, part day out - that would stimulate the growing interest in the future health of the earth. The centre would be self-sustaining, both ecologically and financially. It would also demonstrate how modern technology and the latest architecture, landscape design and responsible farming could work together to revive a despoiled and redundant industrial landscape.
Initially, the Earth Centre was to have been sited at Canary Wharf in London's Docklands. But due to uncertainty over the area's future, Doncaster, near the centre of England, was chosen. It has proven to be a near-perfect second choice. Seventeen million people, says Mr Smales encouragingly, live within a two-hour drive. Then, just in time, he adds: "But whether they should be driving here is another question."
The Earth Centre is linked directly by rail on a branch line from Doncaster; cross the footbridge at Conigsborough station (in sight of the medieval castle) and you step right into the heart of the site. When complete by the turn of the century, the centre will occupy 350 acres of land bordered by the broad and navigable Don.
What can be seen today is an interim landscape, which is divided almost in two between reclaimed land - clear streams, ponds buzzed by dragon flies and fresh pastures feeding sheep - and land scarred by two mines closed in 1979 and 1986.
The Earth Centre occupies a site measuring four miles by about a mile and a half, leased for 99 years. By the year 2000, it will be a place of natural beauty and sound ecology. It will be partly an organic farm, producing meat, fish, grain and vegetables, partly a museum and partly an entertainment venue.
The Earth Centre will be the first of its kind, and is expected to attract up to 2 million visitors a year.
Part of that attraction will be the pastures and gardens, animals and walks, through - when the area is cleaned up - one of northern England's loveliest valleys.
Another source of appeal will be the adventurous new buildings Mr Smales plans to commission from some of Britain's most forward looking architects. Future Systems has already built a model of an exquisite "Ark", intended to be the centrepiece of the project.
This lightweight enclosure, which resembles a vast, yet delicate, butterfly that has come to rest on a hillside in the valley, will be a showcase for energy-efficient, non-polluting technologies for the next century.
"The roof creates a single span under which the various exhibits are arranged on three free-form floors connected by escalators," say Jan Kaplicky and Amanda Levete, of Future Systems. "The highly coloured roof surface is a breathing skin of energy-generating photovoltaic panels. Throughout the year, high levels of diffuse light enter the roof system; for most of the year no electric lighting will be needed in the main public circulation spaces of the building."
Water supplies also will be heated through the roof system, and the structure will be used to collect rainwater.
"The Earth Centre," says Mr Smales, "will generate all the energy it needs, partly through wind turbines and partly through the design of the buildings and the sewage system they will use.
"We were determined to show that a concern for ecology does not have to result in tweedy, woolly buildings. In fact, ultra-modern architecture is often very efficient in its use of natural resources and energy consumption. The other reason for commissioning avant-garde architecture is that we want the sort of people who go for days out to theme parks and leisure centres to be confronted by, to come to terms with, and to enjoy the best our architects can provide."
All food served to the public here will be grown organically at the centre, and visitors will be able to eat in a spectacular restaurant built in the guise of a bridge across the Don and designed by Alsop & Stormer.
Elsewhere on the site, a "clean" factory will make household goods, proving that industry does not have to mean soot, smog and filthy rivers. There will also be a hotel designed on strictly green principles and space for other commercial development.
"We want the Earth Centre to be very much a part of Doncaster and not some exotic bloom," Mr Smales says. "Over the past 15 years the city has lost more than 10,000 jobs. We've encouraged as many people as possible of all ages and backgrounds to come and join in. One former miner persuaded us to let him build and run a radically new fish farm [the aquarium building was erected, like an Amish barn, by volunteer labour during a long weekend] while schoolchildren have planted thousands of trees.
"We open in July, although the main buildings, like Future System's Ark, are dependent on Millennium funding and won't be ready until 2000; when they are we will be able to employ many more people."
This is encouraging news. Here is a chance for creating jobs for a world that feels real, as opposed to one that demands its employees don Casey Jones outfits to drive electrically powered steam locomotives or shovel popcorn into wax-paper buckets at Doncaster's leisure complexes.
The people of Doncaster seem to have known little except leisure - forced and chosen - since the closure of the coal mines and the undermining of the railway works. The Earth Centre project proves that there can be whole earth, proper jobs, modern architecture, holistic agriculture, education and delight after the mere distractions of theme parks and leisure centres.
The Earth Centre has the blessing of local authorities, the European Regional Development Fund and an impressive list of impressive people. From now until the end of the century, it promises to grow into one of the most significant centres showing new ways of nurturing the landscape, new ways of designing buildings and new ways of eating and coping with the undeniable stresses and strains of having too much leisure on our post-industrial, post-mining, post-"The Flying Scotsman" hands.
The Earth Centre, Kilner's Bridge, Doncaster Road, Denaby Main, Doncaster, South Yorkshire DN12 4DY (01709 770566).