Napoleon had a profound influence on Europe. After France's defeat, European leaders convened at the Congress of Vienna and redrew the map of Europe. Europe enjoyed a time of significant peace due to the Continent being ruled by a balance of power.
Yes, in some areas Euopean impeialism was still eient after WW1.
They had to limit their army severely and pay heavy reparations which crippled the nation.
It encouraged western migration by providing settlers 160 acres of public land. In exchange homesteaders paid a small filing fee and were required to complete 5 years of continuous rescidence before ownership of new land
Well the modern study of hsitory helps us not make the same mistakes as we did in earlier history.