On March 16th 1969 John and Yoko arrived at Gibraltar airport to marry in the British Consulate Office of Gibraltar.
Having failed to get married in Paris a few days earlier, John and Yoko chartered an plane to Gibraltar, on the advice of Apple employee Peter Brown, as Gibraltar was a British colony, and Lennon was a British citizen. And they were able to go ahead at short notice.
From the airport they drove directly to the British Consulate Office, where they were married during a 10-minute ceremony.
Within the hour Lennon and Ono had reboarded their aeroplane and flew back to Paris to stay at hotel the Plaza Athénée, where they had stayed the previous days.