This is a killer powerpoint from the Pew research center. The focus is on the issues facing illegal aliens in the United States.  The powerpoint looks at the correlation between individuals staying in the USA and economic prosperity. A geographic breakdown of the total %  of undocumented individuals in the United States is also quite educating, who would have thought Illinois would have a substantial undocumented population?

http://www.pewhispanic.org/2013/09/23/unauthorized-immigration/2-3/

http://www.irishamericanjourney.com/2011/10/irish-ships-to-america.html

This is a very interesting website which describes the ships, routes and yaears of operation. It is interesting to look up images of some of the ships and look at the advancements in size and speed of the ships. One constant is that the ships are crowded with people in all of the images.