History: -In 1501, Rodrigo de Bastidas was the first European to explore the Isthmus of Panama sailing along the eastern coast. -Explored by Columbus in 1502 and by Balboa in 1513. -Panama was the principal shipping point to and from South and Central America in colonial days. -In 1821, when Central America revolted against Spain, Panama joined Colombia, which had already declared its independence. -By July 1831, as the new countries of Venezuela and Ecuador were being established the isthmus would again regain its independence. -Between 1850 and 1900 Panama had 40 administrations, 50 riots, 5 attempted secessions, and 13 U.S. interventions after a U.S. proposal for canal rights over the narrow isthmus was rejected by Colombia. -Panama proclaimed its independence with U.S. backing in 1903. -For canal rights the U.S. paid Panama $10 million and agreed to pay $250,000 each year, which was increased to $430,000 in 1933 and to $1,930,000 in 1955. -In exchange, the U.S. got the Canal Zone, a 10 mile wide strip across the isthmus.