"What evidence do you see that a modern American society based on city living, immigration and diversity, industrial production, and technological
advances started on the trans-Mississippi western frontier from 1865 to
1900?"

there is no photo, therefore i can not answer your question.

the monroe doctrine is the best known u.s. policy toward the western hemisphere. buried in a routine annual message delivered to congress by president james monroe in december 1823, the doctrine warns european nations that the united states would not tolerate further colonization or puppet monarchs.

they sent much needed naval support to the colonists, and were instrumental in the siege of yorktown