The pack of riders cycles on its way during the sixth stage of Tour de Qinghai Lake cycling race from Xihai county to Qilian in Northwest China's Qinghai province, July 12, 2013. [Photo/Agencies]

XINING - Once known as "Atomic Town" in China, Xihai has been transformed into a heaven for cyclists from home and abroad.

Xihai Town, where the country's first atomic and hydrogen bombs were created in the 1960s, sits along the northern bank of the Qinghai Lake in northwest China's Qinghai province.

The once-forbidden mysterious town has witnessed cyclists swarming to attend the Tour de Qinghai Lake, an international road cycling race since 2002.

"They have come here every year for the past 12 years," said Gyumtsho, a 77-year-old woman, who was sitting in the shade watching cyclists pass the finishing line of the fifth section of this year's race, which kicked off on Sunday.

Gyumtsho has witnessed enormous change in the town during the past five decades.

The town, which is 3,200 meters above sea level, was built on the site of Factory 221, launched in 1958 for the development of the country's nuclear weapons.

The factory was closed in 1987 and was handed over to the local government in 1993.