BEIJING, Oct. 1 (Xinhua) -- More than 100,000 people from across the country gathered at Tian'anmen Square in the heart of the Chinese capital to watch the national flag raising ceremony held in drizzles at dawn of Monday, the 58th founding anniversary of the People's Republic.

Wearing raincoats or holding up umbrellas, people -- ranging from gray hairs to toddlers -- began to flock into the square, which was ablaze with the color of 400,000 pots of flowers, at about 5 a.m.

"Happy birthday to you, motherland!" acclaimed 18 undergraduates from the Beijing University of Aeronautics and Astronautics, while seeing the five-star red flag rising at 6:10 a.m. accompanied by the national anthem, "The March of the Volunteers."

"I feel so proud to witness the country is becoming more and more prosperous after going through so many hardships," said 72-year-old Wang Nianshun, from Pingdu City of eastern Shandong Province.

In the futuristic egg-like National Grand Theater, located west of the square, 750 political advisors for the Beijing municipal government watched the drama "Teahouse" written by the late Chinese literature maestro Lao She (1898-1966).

A series of trial performances will be staged at the new landmark in Beijing from Sept. 25 to Oct. 13 ahead of the 17th National Congress of the Communist Party of China (CPC).

At Sunday's National Day reception in the Great Hall of the People, which just lies between the square and the theater, Chinese Premier Wen Jiabao cited the upcoming CPC congress as "a congress of great importance to be held at a time when China's reform and development have entered a crucial stage."

On Monday, flag raising ceremony was also held in many of other Chinese cities, such as Yinchuan, capital of northwestern Ningxia Hui Autonomous Region, drawing tens of thousands of local residents.

In the central city of Changsha, Hunan Province, city administrators organized about 10,000 government employees to clean streets and railway stations to greet the National Day.

Monday also marked the beginning of the "Golden Week" of the National Day holiday, and local tourism authorities have predicted that about 1.7 million people will visit the Chinese capital during the period. Nationwide, more than 150 million people are expected to go on tour.