Between the 1850's and 1880's, more than 5 million immigrants cascaded into America from the "mother continent." Starting in the 1880's, the "new immigrants" (mainly Italians, Croats, Slovaks, Greeks, and Poles) came swarming into the USA. This influx of different nationalities caused problems at first, because they all spoke different languages and practiced different religions. They later; however, helped provide the unique cultural diversity that still exists today in the USA.