The British Cave Research Association (BCRA) have ranked two caves in Việt Nam as the largest and third largest in the world. They are Sơn Đoòng and Én in the Phong Nha-Kẻ Bàng National Park in Quảng Bình Province. Sơn Đoòng also set a Guinness record as the world’s largest natural cave in 2013. — VNS