The area comprising present-day Los Angeles County was first settled by small groups of Native Americans for centuries before the first European contact in 1769 when Gaspar de Portola and a group of missionaries camped on what is now the banks of the Los Angeles River. The name Los Angeles comes from the Spanish language,and it means "The Angels". The name is an abbreviation from the original name of the place. The original name is "El Pueblo de Nuestra Señora la Reina de los Ángeles del Río Porciúncula" (in English, "town of our lady the Queen of Angels of the River Porciúncula"), giving it both one of the longest and shortest (referring to its shortening of "LA") place names in the world. Los Angeles was founded in 1781 while the area was within the borders of the Viceroyalty of New Spain. The area had earlier been explored by two Franciscan priests named Junipero Serra and Juan Crespi and following the Mexican War of Independence the region passed into the hands of Mexico which subsequently ceded control of California to the U.S. in 1848. On April 4, 1850 California became a State of the USA. Los Angeles began half a century of rapid growth after railroads arrived in the city in the 1870s. Los Angeles was home to the Olympic Games in 1932 and 1984. It will host the Olympic Games in 2028. Three times the city broke out in riots, in 1943, in 1965, and in 1992, all due to racism. In 1994, an earthquake killed 72 people and damaged many buildings.