Tham Luang

Tham Luang Nang Non is a cave system in Chiang Rai province, northern Thailand, and in June 2018 it became the most closely watched hole in the ground on Earth.

On 23 June, twelve members of a junior football team, aged 11 to 16, went in after a practice session with their 25-year-old assistant coach. Heavy rain began shortly afterwards and partially flooded the system, cutting off the way out and trapping them deep inside. Rising water and strong currents defeated the search, and for more than a week nobody outside knew whether they were alive.

On 2 July, after working through narrow passages and muddy water, the British divers John Volanthen and Rick Stanton found the whole group alive on an elevated rock about two kilometres from the entrance.

Then came the argument that decided their lives. Organisers weighed teaching thirteen people with no experience enough diving to get themselves out, against drilling a new entrance, against simply waiting for the monsoon to end months later. They chose the dive. It worked, and every one of the thirteen came out.

The operation drew international rescue teams and enormous public attention, and it was not free. Saman Kunan, a 37-year-old former Royal Thai Navy SEAL, died of asphyxiation on 6 July while returning to a staging base inside the cave after delivering diving cylinders to the trapped group. King Vajiralongkorn sponsored his funeral. Getting the water down took the pumping of more than a billion litres out of the system.

The cave sits in a forest park managed by Thailand's Department of National Parks. It is open to visitors, and the chamber where the rescue was staged has become a place people travel to deliberately. It floods in the monsoon, which is the whole point of the story, so the season matters.