Mourning gives way to shouts of 'Long live China' From Hong Kong's teeming business district to the Gobi desert, sirens and car horns wailed as the nation came to a standstill in mourning for the tens of thousands killed in the Sichuan earthquake. People stood in silence at 2.28pm - exactly a week after the magnitude 8 earthquake struck the southwestern province, killing at least 50,000 people and flattening 4 million homes. The sheer scale of the destruction, the human tragedies it caused and the heroism witnessed on every front brought Chinese people together in a show of solidarity. In Beijing, top leaders, including President Hu Jintao and former president Jiang Zemin , bowed their heads in silence outside Zhongnanhai. Earlier, thousands of people gathered in Tiananmen Square at daybreak to watch the daily flag-raising ceremony. The national flag was raised, then lowered to half mast to mark the beginning of three days of mourning. When the clock struck 2.28pm, workers, shopkeepers, students and government officials stopped whatever they were doing. Drivers got out of their cars. Nothing but the blare of vehicle horns in mourning and the wailing of sirens could be heard. In Sichuan, soldiers, rescue workers and quake survivors stopped work and stood silently amid the ruins of homes, schools and hospitals to mourn parents, brothers, sisters and children. Across the nation, traffic froze. Drivers stood beside, or on top of, their cars and bowed their heads. At airports, railway stations and ports, passengers stood in silence. The usually frantic trading on the Hong Kong Stock Exchange dropped to a minimum as brokers stopped work and stood in front of their terminals to show their sympathy for their compatriots. In Macau, casinos lowered their flags to half mast. Once the three minutes of silence had ended, crowds in many cities turned an occasion for grief into a show of public support for the hundreds of thousands rescuers and soldiers still risking their lives to save those trapped under the rubble of collapsed buildings. 'Long live China! Support the people in Wenchuan ,' people shouted in Tiananmen Square, referring to the county at the epicentre of the quake. It was the first public mourning for victims of a natural disaster since the founding of the People's Republic of China, CCTV said. All day, rescue workers kept up their efforts to save those still trapped - even though most agree the chances of finding survivors under the ruins are remote. Meanwhile, workers toiled desperately to build new roads to villages cut off by landslides and rock falls. Powerful aftershocks have been making their task all the more hazardous. More than 200 road builders have been buried by mudslides in the past few days.