HONG KONG — The world is watching as emergency workers in Thailand prepare to rescue 12 boys and a soccer coach who were discovered in a flooded cave on Monday.

They became trapped after entering the Tham Luang Cave on June 23 after soccer practice. Evacuating the group through flooded passages will be difficult and dangerous, experts say, in part because the boys are unlikely to have dived before.

But if the operation succeeds, it will be the latest example of a cave-rescue mission ending in joy, not sorrow.

The sport of caving began in the British Isles in the late 19th century, and the first caving clubs were formed in England in the 1920s and 1930s, according to the British Cave Rescue Council, whose divers are involved in the rescue effort in Thailand. But as interest in caving grew, the council said, the risks of “accidents in places accessible only to fellow cavers increased in parallel.”