The more than thousand-year-old Polish state was one of the richest and most influential countries in the 16th century. During history, Poland's neighbors have sliced and divided the country many times, following the 2nd world war it became part of the Soviet interest region, and only regained its independence after the regime switch. Poland has become the fastest developing regime switching country and joined the EU in 2004. Their agriculture is significant. The large cities and their surrounding areas are the strongest industrial zones. During the socialism, they manufactured by Western standards and licenses, e.g. the Polski Fiat; nowadays these factories are parts of western production giants. The ship manufacturing is high around seaside cities, and the electrical engineering is strongest in Warsaw. Poland's national currency is the Polish złoty.