One of the British divers who helped to save the Thai cave schoolboys had to be rescued from a cave himself after becoming trapped for 28 hours.
Josh Bratchley had been exploring a flooded cave in Jackson County, Tennessee, when he failed to return to the surface on Tuesday.
His fellow divers from the UK spent hours searching for their missing friend, but he was nowhere to be found.
Expert divers found Mr Bratchley waiting calmly in an air pocket.
The alarm was raised after Mr Bratchley failed to return to the surface at 15:00 local time (21:00 BST) on Tuesday.
The authorities were notified in the early hours of Wednesday morning and expert divers were flown in from different US states.
They entered the 400ft cave system at about 18:00 local time, and Mr Bratchley was back on the surface about an hour later.
"He was awake, alert and oriented," rescue official Derek Woolbright told a press conference.
"His only request when he got to the surface was that he wanted some pizza."
Rescue diver Edd Sorenson added: "It was a very silty, dangerous low cave. We came up to the air pocket and shockingly there he was, calm as could be.
"He just said 'Thank you, thank you. Who are you?'"
Mr Bratchley, a former member of the Devon Cave Rescue Organisation, was checked over by medics who found he was "stable" and he declined further treatment.
He was part of a team of British cave diving experts who helped to save 12 schoolboys and their football coach from a flooded cave in Thailand last year.
Mr Bratchley, who is now based at Valley in Anglesey, Wales, as an RAF meteorologist, was later honoured at a reception held by the prime minister and appointed MBE in the 2019 New Year's Honours list.
The diver was praised for his composure by lieutenant Brian Krebs, from Chattanooga Hamilton County Rescue Services.