The Swiss media events of the 1920s were Walter Mittelholzer's Africa flights for aerial photography and cartography purposes. In 1924, he did the first transcontinental flight expedition, starting from the water airport at Zürichhorn via Egypt to South Africa. Mittelholzer's aircraft was a Dornier Merkur (CH-142); it was taken over on March 26, 1931, by the Swissair airline and taken out of service in 1932. In winter 1924/25, Mittelholzer flew to Tehran; the trip lasted a month including two emergency landings. Its flights are considered outstanding technical achievements of its time. In 1930, during another flight to Africa, Walter Mittelholzer was the first pilot to fly over Mount Kilimanjaro.