During 1924, Carl was approached by a group of four businessmen from Detroit and invited to participate in an African trek from Cairo to Cape Town completely on foot, a distance of slightly over 7,000 miles, ultimately taking 11 months to complete. This was the longest trek in the history of exploration. The group, which consisted of a doctor, realtor, lawyer, and the inventor of the Packard 12-cylinder automobile, felt the need of a professional explorer, hence Carl's participation. The purpose of the trip was the sheer accomplishment of the act for all except Carl who wanted the films that such a trip could generate.