Tegel the end of 1948. Tegel is chiefly known for being the location of Berlin-Tegel "Otto Lilienthal", Berlin's main airport. It also houses the Tegel Penitentiary, Germany's largest prison with about 1,700 inmates as of 2007, known from Alfred Döblin's 1929 novel Berlin Alexanderplatz. One of Berlin's largest shopping malls "Borsighallen" is located in the former locomotive manufacturing halls of the "Borsigwerke". There is also the "Villa Borsig" at the shore of Lake Tegel, the former residence of the Borsig family. Today it is a school for future diplomats. Beside this Tegel is an extensive residential district with some industry. With
Knox County Regional Airport operated by the City of Rockland until 1968. It was then turned over to Knox County and renamed "Knox County Regional Airport". Since that time, the airport has been developed, the runways expanded, and an Instrument Landing System (ILS) was installed. Knox County Regional Airport covers an area of 538 acres (218 ha) at an elevation of 56 feet (17 m) above mean sea level. It has two asphalt paved runways: 13/31 is 5,007 by 100 feet (1,526 x 30 m) and 3/21 is 4,000 by 100 feet (1,219 x 30 m). For the 12-month period ending July 31, 2010,