To construct the transcontinental railroad, the Central Pacific and Union Pacific railroad companies built tracks that started in the East and ran all the way to the West. from the West Coast that wound around the mountains. with one starting from the East and one starting from the West, meeting at a midway point. from the West Coast that connected the South with the West.

explanation: we can only guess at how our actions may be perceived in the future. doing something really big like killing lots of people, saving lots of people, affecting the lives of lots of people is a sure fire way of being remembered in historical records. we can also make a difference in the history records by being a small influence on something bigger, whether that is as a civil servant, scientist or artist.

of course you could argue that we all affect history just as tiny cogs in a   bigger machine.

if you mean how do people influence our opinions of things which have already happened, then simply by writing a book which looks at things form a different perspective and trying to convince people that this perspective is more accurate or truthful. people do it all the time i.e. richard the third was a terrible or was he? plenty would disagree, it's just that their views aren't the most widely known.n:

b.

jim crow laws were enacted in northern states.

the pogroms became known as kristallnacht, the "night of shattered glass," for the shattered glass from the store windows that littered the streets. the morning after the pogroms 30,000 german jewish men were arrested for the "crime" of being jewish and sent to concentration camps, where hundreds of them perished.

it was certainly a debatable decision, mainly because it was based primarily on political - and not on legal or social - views. since the congress at that time was led by members of the republican party, and the territory that the tribes wanted to turn into an exclusively indian state was predominantly democratic, the proposal (as expressed in the constitution) did not succeed, but the constitution itself proved to be of crucial importance in the creation of the state of oklahoma, and, most importantly, it guaranteed the involvement of representatives of the indian tribes in the government of the future joint state.  

as a member of congress, i would have voted to ratify the constitution, or at least to have it tabled. ignoring it was an interested and partial decision.