Passage: On 15 October 1934 construction began to build three 800 metres (2,600 ft) long runways to serve the Henschel aircraft plant in Schönefeld. By the end of the Second World War, over 14,000 aircraft had been built. On 22 April 1945, the facilities were occupied by Soviet troops, and the plant was dismantled and demolished. By late 1947, the railway connection had been repaired and agricultural machinery was built and repaired on the site.In 1946, the Soviet Air Forces moved from Johannisthal Air Field to Schönefeld, including the civil airline Aeroflot. In 1947, the Soviet Military Administration in Germany approved the construction of a civilian airport at the site.A stipulation of the Four Power Agreement following World War II was a total ban on German carriers' participation in air transport to Berlin, where access was restricted to American, British, French, and Soviet airlines. Since Schönefeld airport was located outside the city boundaries of Berlin, this restriction did not apply. Thus, aircraft of the East German flag carrier Interflug could use Schönefeld airport, while West German Lufthansa was denied access to Tegel or Tempelhof airports.

Question: When did the building start going up?
15 October 1934