Entrance to Surprising Cave in Halong Bay Vietnam. Sung Sot Cave was allegedly first discovered by the French in 1901, who took it upon themselves to name it Grotte des Surprises, or Surprising Cave, because of its surprising beauty (although the name didnt catch on until a good 40 years later). The cave welcomed its first visitors in 1993, a mere one year before Halong Bay would receive its first bestowment of World Heritage site status from UNESCO