"Special foreign affairs" explained the closure to the public, in a curt notice taped to a window of the police car that blocked the entrance to the symbol of China's splendid past. Disappointed would-be visitors were left to guess that the president of the United States was coming.
The vague wording of the notice was in keeping with the official tone that the Chinese authorities have adopted for Mr. Obama's first visit here. Tuesday's People's Daily, the official organ of the ruling Communist party, for example, relegated coverage of the president's activities in Shanghai to the bottom left-hand corner of the front page.
It splashed coverage of the funeral of a former deputy prime minister across the top of the page.
"They don't want this trip to be about Obama," says Russell Leigh Moses, a political analyst here. "They want it to be about China's rise."
On a day that mixed high affairs of state with simpler tourism, the president got his only chance to speak directly to the mass of the Chinese people. Alongside Chinese President Hu Jintao, he made televised comments at the end of the two leaders' three hour meeting.
No displays of charm allowed
On his three-day trip to China, Obama will not be afforded the opportunity he has enjoyed on other foreign tours – such as when he addressed a rapturous crowd of 200,000 in Berlin – to project his personable charm.
This is not altogether unsurprising. Chinese political protocol and tradition leave little room for rock stars, or even for much direct contact between leaders and their people. Chinese citizens do not expect to get close to their top leaders.
The current crop of Chinese rulers seems especially attached to the pomp of major speeches and parades in preference to the give-and-take of debate with the citizenry.
Prime Minister Wen Jiabao, sometimes known popularly as "Grandpa Wen," has been known to display the common touch; it was he who waded into earthquake stricken villages in Sichuan last year to comfort grieving families and reassure them that their government cared.
Hu doesn't warm to spontaneity
Mr. Hu, however, generally seems highly uncomfortable on the rare occasions on which he is shown talking to ordinary people. So uneasy is he with unscripted public events that he has reversed the policy of predecessors such as Jiang Zemin and Deng Xiaoping, and does not give press conferences. Tuesday's "joint press conference" with Obama was in fact simply an opportunity for the two leaders to read prepared comments. No questions from the assembled journalists were permitted under rules the Chinese hosts imposed.
White House officials say they did not push to give their boss the kind of opportunities for public interaction in China that he has relished elsewhere.
"Once we had internally settled on wanting to do a town hall [meeting], that is the only outreach event we discussed and worked out with the Chinese hosts," said a senior administration official.
A carefully screened 'town hall'
Asked whether the Chinese side had deliberately curtailed Obama's chances of showing how popular he is here, deputy Foreign Minister He Yafei insisted that "Obama's agenda was agreed by both sides," and that the town-hall event in Shanghai on Monday offered the US leader an opportunity for "exchange with the Chinese public."
That meeting, with about 400 students, was televised only on local TV, however, and only around 7,000 people in China managed to log on to the live streamed version carried on the Internet, according to ConnectSolutions, the firm that helped the State Department organize the webcast.
The US president has one more chance to make his views known to a wider audience than the senior officials with whom he has scheduled meetings on Wednesday. He will be giving an interview to Southern Weekly, one of the bolder Chinese newspapers that has regularly clashed with the authorities, in what is clearly a sign of US support for a freer flow of information in China.