The vast expanse of Tiananmen Square is surrounded these days by a high metal wall. Behind it, the big stone blocks on which millions of Chinese have walked, marched, demonstrated and taken souvenir photographs during the last 40 years have been dug up.
Machines and men work at laying a new granite surface. The renovation is timed for completion before the celebrations of the 50th anniversary of the People's Republic of China on October 1st.
Many Beijingers suspect, however, that the authorities have another objective, to keep the immense plaza, the symbolic heart of China, closed to the public and so prevent any unauthorised demonstrations between now and June 4th. That was the date 10 years ago when troops cracked down on students demonstrating for democracy in Beijing.
The issue is still extremely sensitive in China. It is a taboo subject in the media. When the most senior official to be jailed in the affair wrote an open letter to the Chinese leadership this week calling on them to reverse their "wrongful assessment" of the pro-democracy movement, it was suppressed. But Mr Bao Tong warned them: "The history of bloodshed remains in people's hearts; they will not forget."
Mr Bao was an aide to the former Communist Party general secretary, Zhao Ziyang, who was ousted by hardliners after the crackdown for sympathising with the students. He was released from a seven-year jail sentence in 1996 but is kept under close police surveillance.
"No one can ever successfully cover up such an event," Mr Bao said in his letter, addressed to President Jiang Zemin. "It is only a matter of time. There is no other choice but to reverse the wrongful assessment of June 4th.
"You may choose whether it is done now or later, and whether it is done through good judgment or by force."
A softening of the verdict would have great benefit, he went on. It would "win the hearts and minds of the Chinese people, as well as sincere respect and applause from around the world . . . Using hundreds of thousands of troops to crack down on unarmed students and civilians was something the Chinese Communist Party should never have done. "And letting the wrongful assessment of the events remain without reversal means the continuation of severe pain for the Chinese people."
The Chinese leadership has adamantly refused to reopen the Tiananmen Square incident, and is unlikely to do so while Mr Li Peng, chairman of the National People's Congress, who declared martial law in 1989, remains in a senior position. The most prominent pro-democracy leaders are still in prison.
The State Council, or cabinet, declined to comment on the letter, and Mr Bao has been denied a passport to visit his son in the United States. Meanwhile President Jiang is said to keep a close watch on the activities of ousted general secretary Mr Zhao Ziyang, who is prevented from making contact with his former political secretary.
President Jiang Zemin arrived in Geneva yesterday to protests at China's record on human rights and Tibet. Several dozen protesters from Amnesty International and Tibetan organisations peacefully gathered in front of the UN's Palace of Nations.