Philadelphia had a more tolerant culture since it was founded by English Quakers, and Quakers were famous for preaching tolerance and promoting peaceful convivence among different groups of people.
Philadelphia was also at first the largest city of the U.S., and after, the second-largest, only lagging behind New York City. This meant more economic opportunities, including African Americans, who could find employment in the city's industrial sector.
The Battle of El Alamein marked the culmination of the North African campaign between the forces of the British Empire and the German-Italian army commanded in the field by Erwin Rommel in World War II.