3分钱的代价买下密西西比河沿岸的土地。你知道这些土地现在价值多少钱吗？

CREDIT: "View Down the Mississippi from Fort Snelling, Minnesota" Detroit Publishing Company between 1880 and 1899. Touring Turn-of-the-Century America: Photographs from the Detroit Publishing Company, 1880 - 1920, Library of Congress.