World War II started in full force with the invasion of Poland. When victory was declared, Poland was not independent. It had simply had the Hitler/Stalin-led invaders replaced by just Stalin. Poland has a population of 39 million, and about 20 million people around the world claim Polish descent. The idea of Poland as a recognisable territorial entity began in the 10th century with the baptism of its first historically documented ruler in 966, making Christianity the official religion of his subjects. The Polish-Lithuanian Commonwealth was joined through personal union of the King of Poland and Grand Duke of Lithuania, forming one of the largest multi-ethnic powers in Europe in the 16th & 17th century. Growing weakness led it to be partitioned amongst neighbours (1772-95) and it only regained independence post World War I. According to the Global Peace Index for 2014, Poland is now one of the safest places in the world to live.
Mieszko I - First ruler of Poland
Polish Diaspora in the US