Traveling by land from Europe to China entailed avoiding robbers and soldiers from possible unfriendly nations. Sea travel was possible by sailing around the southern tip of Africa and then finding silk trading ports in India and China. For this reason a sailing route traveling west from Europe was a hope to find a better way to reach Asia.
Answer: In the late 1800's and early 1900's, urban areas of the United States attracted thousands of immigrants because of the ready availability of industrial jobs.