That is why Wei's cottage is important. 'As long as you stay in my house, police won't come and deport you - not because they respect an old man, but because the law does not address visits to me,' he said.

Professor Susan Keates from Oxford University in Britain drops a typical note after a few memorable nights here: 'Wei Qi's station at Donggutuo is a very nice place to stay ... and one is made to feel at home.'

If Nihewan becomes a hotspot in the future, it will be because it has an interesting history. Until about 40,000 to 30,000 years ago, the area was a lake with hominids living on its shore for at least two million years. Sometimes the water would rise and flood the settlements - bad news for our ancestors, but good news for palaeoanthropologists seeking evidence of early humans.

In 1923, an inexperienced but rich American geologist named George Barbour strolled into the basin and was amazed when he saw the ancient sediments from the lake. Although he guessed wrong about how old they were and found basically nothing, Barbour invited Pere Licent and Pierre Teilhard de Chardin, two of the most brilliant prehistoric archaeologists of that time, for a visit.

Licent and Chardin not only pushed the sediment's age to over a million years but also found, among many things, a flint tool. It was the oldest stone tool found at the time - so old, in fact, that even Chardin himself had suspicions about its authenticity.

But just as they were planning another dig, a Peking man skull was found at Zhoukoudian west of Beijing, and the world's attention immediately shifted. Nihewan was largely forgotten, except by Professor Pei Wenzhong , the discoverer of Peking man.

The discovery made Pei an instant international celebrity in palaeoanthropology, but when the People's Republic was established in 1949, the Communists made him a figurehead in the field, and he spent the rest of his career denying the existence of Nihewan Apeman, reasoning that there simply couldn't be anything older than Peking man.

Pei used his influence to rebuff all evidence of human activity scientists had brought to him. Then in 1982, Wei found a huge hominid settlement at Donggutuo and took a few samples to Beijing for Pei's examination, hypothesising that the samples were more than a million years old, which would be twice as old as Peking man.

'He said nothing, but I guess he had accepted it,' Wei said. He could only guess, because Pei died of a heart attack a few days later.

Afterwards, palaeoanthropologists around the world began to take notice. Professor John Desmond Clark from the University of California Berkeley, a man with enviable financial resources and solid reputation based on his African studies, obtained permission to enter China in 1990 and stayed for two years. With Wei as his partner, a joint research team was formed and spent two years removing 30 cubic metres of earth, but little of value was found.

Despite the disappointing result, Wei said he enjoyed working with the Americans.

'The Americans liked to boss people around,' he said. 'They always thought their methods and ideas were the best, and not every Chinese could immediately accept these cowboys. But they brought us new equipment, skills, techniques and - probably more importantly - new ways of thinking. The project marked the beginning of the modernisation of Chinese palaeoanthropology. To be honest, we were digging stone artefacts like farmers digging potatoes before they came.

'Palaeoanthropologists from different countries work in different styles. There's always something to learn from others. History has taught us a good lesson: if we shut the door and refuse to let strangers in, ridiculous ideas will breed and prevail.'

But China has had a reluctant view towards foreign scientists ever since they looted ancient artefacts in the name of research at the turn of the 20th century. In 1930, Nationalist legislators passed a law forbidding any ancient artefacts leaving China and severely restricting the activities of overseas scientists in the country. The Communists enforced the same policy except for a brief period of opening to the Soviets in the 1950s.

Although several joint excavations were approved in the 1980s, as the country has gained financial and scientific self-confidence, the government has been less willing to let foreign scientists have access to the country's unique resources.

But Wei said today's scientific considerations should have priority over any past and present xenophobic feelings. 'The government should lift the bans on foreigners' visits,' he said. 'Nihewan belongs not only to China, but also to the rest of the world.'

After the Americans left, Wei continued the search in Nihewan. 'He walked every gouge and tor on this most splendid page of geographical history ... with zest greater than Louis Leakey [founder of the theory of human origin in Africa],' said National Science Award winner Professor Liu Dongsheng .

Today, more than 100 prehistoric sites dated between 10,000 and 2 million years ago have been found in the Nihewan Basin. More than 40 of them are estimated to be more than a million years old. It is an extraordinary achievement, because for the rest of China the total number of one-million-year-old sites is merely six, and none of them is nearly as old as those in Nihewan.

More and more researchers worldwide put the importance of Nihewan, in our understanding of human evolution, on par with the legendary Oduvai Gorge in Tanzania, which has set the earliest record of human existence at about 2.6 million years ago.

But unlike Oduvai, where hundreds of human fossils have been found, including the famous skeleton of Lucy, Nihewan has offered none.

From a Chinese standpoint, 'there couldn't be anything more disappointing in the entire history of palaeoanthropology', Wei said.

And yet nothing could be more exciting, too, because if a human fossil is found in Nihewan sediments as old as Oduvai, the theory of humans moving out of Africa will be thrown entirely out of kilter, and current palaeoanthropology textbooks will have to be rewritten.

While most of the 'tourists' coming to Nihewan now are scientists, there's another group of people equally eager about the discovery of Nihewan Apeman - Yangyuan county government officials.

Officials are investing 100 million yuan (HK$114 million), nearly half of the county's gross domestic product, this year to build a museum, several paved roads and hotels. 'Few Chinese have ever heard of Yangyuan, not to mention foreigners', said Hou Wenyu , director of the County Cultural Bureau. 'We don't have any coal, ore, heavy industry or trade. The apeman is our only hope. It will definitely make us rich and famous.'

But Wei, who has spent an entire career in the basin, isn't so sure. 'It's like playing a game of hide-and-seek, and your opponent is God. We should enjoy the process,' he said.

He definitely should, as now even his wife has agreed to come.

Record discovery

Just six million-year-old sites have been found in China outside the Nihewan Basis, while the basin has: 40