The first country to defeat the Soviet Union in war. The country that defeated the Teutonic knights, ending German supremacy for hundreds of years. The occupied nation with the largest Nazi resistance movement in World War II. The first Eastern Bloc country to break free of communism. The second country in the world with a written constitution (after the U.S.), and the first in Europe.
Not to mention their rather extremely beautiful women.
I'm not Polish, but they've got one of the most interesting histories in the world.