Why was rail concentrated in the east before 1870 and in the west after 1870?

During the 1960s, how did the neural movement promote the chicano movement

In italy, the distance between milan in the north and palermo, sicily, in the south is about 550 miles. in the united states, the distance betweenboston, massachusetts, and savannah, georgia, is about 900 miles. do you think the american revolutionaries of 1776 in the 13 colonies faced some of the same challenges as the patriots who struggled for italian unity in the 1860s?  

Why did president johnson decide not to run for reelection in 1968?