In its article, SCMP looks back at the journey to discover the world's largest cave of a local farmer named Ho Khanh. After several times of failures, in 2008, Khanh finally found the cave entrance, and he contacted the royal expedition team of the UK, which he guided in their search of new caves in Phong Nha – Ke Bang. The cave was measured at 5km long, boasting underground river systems, thriving jungle ecosystem, 400-million-year-old fossils, and spectacular geological formations. Son Doong cave is also home to several species of plants and animals, that exist nowhere else on earth. In 2018, a team of UK cave experts discovered that, Son Doong cave is at least 30% larger, and much deeper than previously reported. In addition to Vietnam's Son Doong cave, the list of the seven most beautiful underground attractions in the world includes Tham Luang cave (Thailand), the Paris Catacombs (France), the Cold War Tunnel (Albania), and others./.