Workers are busy building the Zhangye Olympic Sports Center. [Photo/zgzyw.com.cn]

Workers are seen busy welding the steel structure roof of a swimming pool at the construction site of the Zhangye Olympic Sports Center in Zhangye, Gansu province, on Mar 17.

The project covers an area of over 139,000 square meters, with an estimated investment of 440 million yuan ($64.5 million). Upon completion, it will become the city's largest and most versatile public service place for fitness.