1493 - Christopher Columbus first sights the island now known as Puerto Rico.
1497 - Portuguese navigator Vasco da Gama reaches the Cape of Good Hope
1820 - Antarctica sighted by US Navy Capt Nathaniel B Palmer
1903 - Hay-Bunau-Varilla Treaty gives US exclusive canal rights in Panama
1918 - Latvia declares independence from Russia
1956 - Morocco gains independence.
