Maximum of 900 guests allowed to visit Son Doong in 2018

Maximum of 900 guests allowed to visit Son Doong in 2018

Oxalis tour operator, the only travel company allowed to organise tours to the well-known Son Doong Cave, in the central province of Quang Binh, officially opened its ticket sales to explore the world’s largest cave for 2018, with a route of four days and…