From April to October in 1944 the Danube was the target of the RAF's Gardening operiation which ment of laying mines in the river to disrupt the most important oil supply route from the Romanian fields to the refineries of Wien and Pozsony. The missions were executed by the 205. Group (they flew Wellingtons and Liberators) and were scheduled in between the usual bombing runs against Italian, Balkanite and Hungarian targets.