Hungary–Romania relations
During World War II, Hungary and Romania became allies and participated in the war against the Soviet Union. But after the coup on 23 August 1944 Romania switched sides and fought against Hungary. Consequently, Soviet and Romanian troops invaded Hungary, occupied Northern Transylvania by October 1944 and re-established the Romanian administration in the region in March 1945. The 1947 Treaty of Paris reaffirmed the borders between Romania and Hungary as originally defined in Treaty of Trianon 27 years earlier, thus confirming the return of Northern Transylvania to Romania.
Strategic bombing during World War II
The first airstrikes against Romania occurred after Romania joined the Third Reich in June 1941 during their invasion of the Soviet Union. In the following two months, Soviet Air Forces conducted several attacks against the King Carol I Bridge, destroying one of its spans and damaging an oil pipeline. However, after the successful Axis powers Crimean Campaign and overall deterioration of the Soviet position, Soviet attacks against Romania ceased.