Union of European Nations.
In this timeline, when WW-II ended Germany and Italy had to give little land for peace. Germany was still divided in two but only Kaliningrad was given to the Soviets. Eastern Germany could keep the land that in OTL were given to Poland. Italy had to give Libya under English control for at least ten years.
In 1956 the Union of European Nations was formed, which was made of France, UK, Italy, West-Germany, the Netherlands, Belgium and Luxembourg. 1965 Austria and Ireland joined the UEN. In 1966 the UEN became one country and adopted the Euro. The UENs economy grew massively and in 1970 Switzerland joined. Inspired by the UENs success the Northern states of Europe formed the Northern Union. In 1990 Eastern Germany joined the UEN. The UEN never gave up its colonies of Algeria, Tunisia and Libya giving a huge oil supply.
The UEN has always tried to keep its citizens from buying foreign products and has succeeded well. Therefore the UENs economy is the Greatest in the world.