If we start to travel from the Mississippi River westwards to the Pacific Coast, than the starting point is a lowland, vast one, as we continue to go towards the west we will encounter high mountains, the Rocky Mountains more specifically, and the elevation will go up to 4,400 meters above sea level, than we will go down, elevation wise, to the high plateaus and will be on elevations between 1,000 and 2,000 meters, and after we go up again to almost 4,400 meters as we cross the Cascade Mountains. After the Cascades we go gradually downwards towards the lowlands, where we will first go a bit bellow sea level, and than little up in the lowlands along the Pacific Coast, and at the end reach a point of zero elevation.
Based on our nationalities
The correct answer is that international volunteers fought on the Republican side in the Spanish Civil War.
The Republican side was formed around the Government, formed by the Popular Front, which in turn was composed of a coalition of Republican parties - Republican Left and Republican Union - with the Spanish Socialist Workers Party, which had joined the Marxists - Leninists of the Communist Party of Spain and the POUM, the Syndicalist Party of anarchist origin and in Catalonia the left nationalists led by Esquerra Republicana de Catalunya. It was supported by the labor movement and the UGT and CNT unions, which also pursued the social revolution. The Basque Nationalist Party had also opted for the republican side, when the republican courts were about to approve the Statute of Autonomy for the Basque Country.
Although it received hardly any external support from the allied powers of the Second World War, due to the International Non-Intervention Committee, the support of the USSR, which together with Mexico together with France and Poland at the beginning of the contest, stand out; they contributed large quantities of military equipment and advisors, notoriously also the support of what were called the International Brigades.