Coordinates: 54°23′18″N025°5′42″E / 54.38833°N 25.09500°E / 54.38833; 25.09500Rūdininkai or Rūdninkai airbase is a former Soviet airbase in Lithuania located 36 km (22 mi) southwest of Vilnius and only 16 km (10 mi) from the border with Belarus. It is surrounded by Rūdininkai Forest, the fifth largest forest in Lithuania. It was part of a larger training complex encompassing about 100 km2 (40 sq mi). Bomber pilots from various Soviet republics were trained to accurately bombard rows of obsolete military equipment, cars, tanks, even airplanes. Various explosives, usually air-dropped bombs weighing 50–100 kg (110–220 lb), are still found in the abandoned facility. The largest bomb, detonated in 2007, weighed 3,000 kg (6,600 lb). Rūdininkai airbase is the largest territory of 222 areas in Lithuania, covering the total of 250 km2 (97 sq mi), that are still contaminated by old explosives.