A sand mandala is on display in Dunhuang city, Northwest China's Gansu province, Sept 20, 2017. It took 16 Tibetan monks half a year to finish the mandala, which is 6.5 meters in diameter and declared to be the biggest in the world by Hong Kong-based World Records Association. Mandala, an exquisite religious art of Tibetan Buddhism, are created by an intricate process that involves a variety of crafting, including hand painting, copper casting, sand laying, wood carving, and hand embroidering. [Photo/China News Service]