Mark Thatcher was an adult when he went missing in the Sahara Desert, but that disappearance still set off an international search. Mark went missing while driving a Peugeot 504 as part of the Paris-Dakar rally. The rally took drivers from Paris to Dakar over a number of legs, but Mark and his co-driver Anne-Charlotte Verney, as well as their mechanic, drove off course and seemed to have disappeared. 

After it was announced that Mark had disappeared, military groups were organized to search for him, and his father also flew to Dakar. He was found six days after he went missing, 50 kilometers off course. The search was a dramatic affair, but one that ultimately caused some international embarrassment for Mark’s mother, who was serving as Prime Minister at the time. 

Source : https://www.distractify.com/p/mark-thatcher-now