Flagler next sought perhaps his greatest challenge: the extension of the Florida East Coast Railway to Key West, a city of almost 20,000 inhabitants located beyond the end of the Florida peninsula. He became particularly interested in linking Key West to the mainland after the construction of the Panama Canal was announced by the United States in 1905. As the closest deep-water port in the United States to the canal, Key West was positioned to take advantage of significant new trade with the west that would be enabled by the opening of the canalthis, in addition to the city's existing involvement with Cuban and Latin American trade.