The world's first jet engines were already available shortly before the end of the Second World War, but they had not been developed to a high enough standard to take part. This changed after 1945 when, on both sides of the Iron Curtain, one technological development surpassed the others and records tumbled almost every week. The era of the piston engine was finally over and jet fighters now dominated the skies. By the mid-1950s their speed had already reached double that of the speed of sound; an achievement which a few years earlier, would have sounded to many like science fiction.