A huge crowd materialized in Beijing's Tian'anmen Square on Tuesday evening to celebrate the 70th anniversary of the founding of the People's Republic of China.

A group of teenagers playing accordians, sang the classic song Me and My Motherland as they strolled past the Golden Water Bridge at the foot of the Tian'anmen Rostrum, which separates the Forbidden City from Chang'an Avenue.

The singers were joined by tens of thousands people, who showed up for the grand gala in Tian'anmen Square. President Xi Jinping and other Chinese leaders and guests lined the Rostrum.

"It might have been the biggest crowd ever to form in such a short interval at such an iconic site," Zhang Yimou, chief director of the gala told Xinhua News Agency.

"The teenagers suddenly appeared on the Golden Water Bridge and started the gathering. People came and sang along with them. All the participants were amateur singers. As more people joined the crowd, it was very touching."

Zhang, a two-time Oscar nominee who directed the stunning opening and closing ceremonies of the 2008 Beijing Olympic Games, added that such gatherings had become popular, particularly among younger Chinese people.

"The crowd gathering was used as a part of the evening gala and was a great way to celebrate the day with fun and spontaneity," he said. "It highlighted the lively and jubilant atmosphere of the new era."

The Tuesday evening gala created quite a buzz on social media. Thousands commented online. One person posted: "It's a great show for the country's birthday." Another lauded the music: "The song Me and My Motherland is actually contagious and fills me with emotion."

The song Me and My Motherland was written by lyricist Zhang Li and composer Qing Yongcheng in 1985 and was first performed by Chinese singer Li Guyi. With its smooth melody and catchy lyrics, it has been popular with Chinese audiences for generations.

In February, a series of crowd-based activities was launched by CCTV to mark the Chinese Lunar New Year. People also sang Me and My Motherland, and various renditions of the song broke out in cities around the country.

"I have rearranged the song with four different versions in the past six months, and the crowd in Tian'anmen Square on Tuesday was the largest to sing it," said Huang Kairan, composer of the China National Symphony Orchestra. "This version of the song was arranged for participants from different occupations and a wide range of ages-teenagers, soldiers and even the hearing-impaired, who sang the song using sign language. We sang it together to express our best wishes for the country."

As one of the major anniversary events, the 90-minute gala started at around 8 pm with fireworks rocketing into the sky. Celebrated Chinese artist Cai Guoqiang joined the effort as chief fireworks director. Amid large-scale performances, six fireworks showcases were presented, including one that displayed the number 70 over the square.

More than 1,000 musicians from 16 symphonies across the country and a large choir comprising more than 1,400 primary and middle school students performed together.

Another highlight involved more than 3,000 performers carrying light panels. They moved to portray different images as the panels changed, displaying images such as a huge national flag, the Great Wall and a white peace dove.

The panel technology had been used in other places for anniversary celebrations. For example, about 8,000 organic light-emitting diode panels were used during a gala entitled "Stride Forward, the Nation", at the Great Hall of the People in Beijing on Sunday.