Artisans use threads and ropes to stretch drumheads of porcelain drums in Yen Son, Tuyen Quang Province of Vietnam, on Dec. 1, 2018. The porcelain drum is a unique musical instrument of Cao Lan ethnic people in Yen Son district. The drum's body is made of kaolin clay while the two heads are made of bull or goat leather and skin of pythons or basilisks. Porcelain drums are usually used for festivals and weddings. (Xinhua/Ngo Minh Tien)