The former Venlo-Herongen Air Base was built between October 1940 and March 1941 as a German Fliegerhorst on the Groote Heide (Large Heathland) near Venlo. It was given the name Fliegerhorst Venlo. The complex had two runways of 1,450 and 1,200 metres and was equipped with the most modern safety installations, radio equipment and night lighting. It was expanded several times in the following years. The runways were on Dutch territory and the other buildings were divided between Dutch and German territory. A road network with a total length of approximately 48 kilometres ran through the Fliegerhorst between the hangars, shelters, workshops, casinos, football and tennis courts. Between January 1943 and August 1944, approximately 75 to 100 attacks were carried out on the airbase, with many bombs landing outside the airbase. On 3 September 1944, the base was attacked by a 114 RAF aircraft, causing the take-off and landing area to be decommissioned. German equipment was taken off the base on 5 September. Almost everything that was still standing, was blown up by the German army in the following days. After the Americans liberated Venlo on 1 March 1945, they renamed it Y-55 and used it from 10 March 1945 to 20 September 1945. On Dutch territory, most of the remains have been thoroughly cleaned. On German territory, almost everything is still in the state it was left behind.