Ft. sumter is most significant for being

Ft. Sumter is most significant for being the place were the first battle of the Civil War took place.

Explanation:

Fort Sumter is a garrison on a coastal island in the Atlantic Ocean at the entrance to Charleston Bay (South Carolina). The construction is named after General Thomas Sumter (1734-1832) considered a hero of the American War of Independence.

Its historical importance is that it was there that the first battle of the Civil War took place on April 13, 1861. On April 28, 1948, the US Congress established the fortification as a national monument.

norsemen from northern countries had made earlier journeys

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.