Geography had a profound impact upon Ancient Greece. The deserts brought heat, the coastline helped with trade, and the oases brought grass & water. The deserts, coastline, and oases of Arabia helped shape the Arab way of life.
Abolitionists employed each of these techniques. The underground railroad was a system used to help slaves escape. Religion played a critical role in helping people realize the immorality of slavery and armed force was used in certain cases (occasionally resulting in even greater problems or backlash from slave owners).
Vietnam was divided by the 1954 Geneva Agreement that followed the French defeat at Dien Bien Phu. The last Americans were withdrawn from the South on April 30, 1975, following the Communist victory over the Saigon forces supported by the United States.
Catherine the Great was not actually Russian at all. She was born a Prussian (German) and married Peter the Great, who adored the Prussians. She was a German leader of the Russian throne after overthrowing her husband.