Seward was dedicated to expanding America's territorial holdings and made a series of abortive attempts to purchase land in the Pacific and the Caribbean. Seward's only major success in this respect came in 1867, when he negotiated the purchase of Alaska from Russia for $7.2 million in gold
Spain used the mission system as their main method of colonizing because they had new spain already so they could easily expand from that point. Also it allowed them to spread catholicism.
In both Europe and many parts of the New World was the belief on a scientific notation that people from the African continent were somehow inferior specimens of Homo Sapiens.
