The Tongva people lived here by 500 B.C. as hunter-gatherers rather than farmers, with Coast Live Oak trees significant to their culture and acorns a staple of their diet. Mission San Gabriel Arcángel was founded in 1771; although Franciscans established the mission, by 1833 the Mexican government had taken over the land and granted it to individuals. Present-day Monrovia is made up of parts of Rancho Azusa de Duarte and Rancho Santa Anita. In 1886 Monrovia began with the first lots offered for sale on May 17, and in 1887 prohibitionists pushed for incorporation to eliminate the sale of alcohol, making prohibition the new city's first order of business. Monrovia is the fourth oldest city in Los Angeles County after Los Angeles, Santa Monica, and Pasadena. From 1890 to 1945, the climate and soil of the San Gabriel Valley supported a major citrus era, with groves set out in the mid-1880s and continuing until the end of World War II. From 1903 to 1955, Dr. Francis M. Pottenger operated the Pottenger Sanatorium on what is now the 600 block of North Canyon Boulevard as a place of respite for people suffering from consumption and asthma. During a resurgence that began in the 1970s, Monrovia undertook major business and neighborhood revitalization, and in 1995 the city and community received the All-America City Award from the National Civic League.