The activities that most demonstrated Americans' belief in Manifest Destiny occurred during the 19th century, while thousands of settlers moved west and displaced thousands of natives.
Because they controlled the gold & salt trade.
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The main difference between the plans of Columbus and da Gama mainly differ in the way they tried to reach the continent, while Columbus was going for a much riskier option and wanted to reach Asian through unexplored ocean by going in a westward direction, da Gama was going for a safer option by traveling near the continental mainlands and was going south to go around Africa and than eastward towards the already known direction for Asia. This lead to different results, Columbus unintentionally managed to discover a whole new world for the Europeans, while da Gama managed to open up a route towards Asia that was clear of any charges or passing through the waters of some empire.
This settlement was founded by a French explorer named Robert Rene de La Salle and by him was named Fort St Louis in honor of his King, Louis the XIV of France. Actual site of the fort or settlement on the bluff . Hope it helps