The world’s largest cave found in Phong Nha-Ke Bang National Park in central Vietnam opens for pilot tours this month.

Son Doong Cave was explored in 2009 by the British Cave Research Association with the expedition detailed in National Geographic.

Now, Howard Limbert, who led the 2009 expedition has teamed up with Oxalis to offer tours this month, and in February and March 2014. He will lead the two pilot tours this month and will be joined by other caving experts in 2014.

Limbert told me that the pilot tours have been permitted by Quang Binh province and future public tours of the cave will depend on the success of the upcoming pilot tours.

“These pilot tours will be safe and environmentally sustainable. We proposed this tour to the Quang Binh authorities as an alternative to major investment and construction in order to make the cave a mass tourism site. This would have damaged the core zone of the National Park and World Heritage site. This would undoubtedly have lost the World Heritage status for the park.

“We shall be taking in groups of six people who all have to complete a medical/fitness questionnaire to ensure that they can manage what is quite a strenuous tour.”