Beijing ? Giant screens were set up in parks so Beijing residents could share in the glory of their city hosting the lavish Olympics opening ceremony Friday. But in at least one park, security guards shut the gates and shooed people away.

Main roads were quiet, with police cars stationed at every intersection. In old Beijing neighborhoods, security volunteers in Olympic T-shirts sat on street corners or cycled around looking for any hint of trouble.

After seven years of buildup and billions of dollars in preparations, the capital declared Friday an unofficial holiday and encouraged millions of residents to stay home or use public transport. Officials said it was an effort to reduce traffic congestion as 91,000 people attended the opening of the Beijing games.

The Olympics have been a huge source of national pride. But they have also come at a cost for the residents of Beijing, a city of 17 million where half the cars have been taken off the roads, and many migrant workers and students have been sent home to reduce pollution and congestion.

As fireworks lit up the smoggy skies above the National Stadium to begin the ceremony, the gates of one park in the north of the capital were promptly locked with only a few hundred people inside. Several dozen residents called on police to open the gates and let them in, but were denied.

“You’re not letting ordinary people into the park,” shouted one elderly woman carrying a foot stool and grabbing the bars of the gate. She said she was too scared to give her name. “Who has the right to control the park?” she demanded.

Inside the park, Yang Shushen, another resident, watched the ceremony on one of the large screens set up to encourage festive gatherings.

“I feel China is strong now,” said Yang. “China has an ancient culture, and this shows how the culture has developed.”

In alleyways near the ancient Lama Temple, people watched televisions in hair salons and restaurants. But outside, the streets were mostly empty except for security volunteers.

Zheng Zhifeng, 29, who runs a tailor shop with his wife near the Lama Temple, said there were no customers as everyone was at home watching the ceremony on TV.

“We didn’t think the Olympics would be this grand,” he said. “It’s very exciting.”

For Chinese dissidents, human-rights lawyers, and other activists who have dared to challenge the communist government, the start of the Olympics meant more surveillance and tighter restrictions.

“I have no plan for tonight,” Jiang Tianyong, a human-rights lawyer, said from his home. “It’s not my Olympic Games. It’s not the games for the ordinary people.”