It has been two decades since the first train on Guangzhou's Metro Line 1 rolled onto the tracks, and a series of events were held to celebrate the anniversary at Wansheng Plaza in the city on June 28.

Guangzhou's Metro Line 1 opened on June 28, 1997.

During the event, the Guangzhou Metro Company honored its veteran employees and invited more than 100 people to share in the celebrations.

To mark the occasion, the city's oldest subway train is being overhauled and will be back out on track from June 28 to July 31, according to the company. People can check its time table on the Guangzhou Metro mobile app.The organizers have collected some old photos and stories about Metro Line 1 via the company's official Sina Weibo and Wechat accounts, and displayed them on the special train's carriages.

"The first English sentence l learned was 'The next station is Gongyuanqian'," one passenger recalled. Another one said he thought that he had boarded an inter-city train the first time he took the metro.

The first train of subway Line 1 re-opens to the public in June after an overhaul. [Photo by Gao Hetao/Guangzhou Daily]

A photo exhibition is also being held at Wansheng Plaza, where people can take a closer look through the 20-year history of the city's subway.

People can also write postcards at the 13 stations along its route to send their best wishes to the 20-year-old train. They can re-open the mailbox 10 years later. The activity will last to July 7.

Guangzhou Metro has also released a special-edition one-day ticket costing 20 yuan ($2.96), which passengers can purchase via its official app or WeChat account.  

Guangzhou Metro has 10 lines and carries 7.3 million passengers a day on average.