Michael Portillo strikes oil in the suburbs of Los Angeles, contemplates his navel in the orange groves of Riverside, makes a California Roll and paints a pretty picture in Laguna Beach. It is Mexican Independence Day and the locals are celebrating the country's hard-won independence from Spain in the early 19th century. There is dancing, singing and feasting in the streets and Michael is up for joining the party. He learns that one in two of the population of LA is Latino, mainly of Mexican descent, and hears after only a few decades, Mexico lost half its territory and California became part of the United States. Michael learns the secrets of backyard oil drilling in Los Angeles, home to the largest urban oil field in the United States. Nodding donkeys are everywhere - in residential neighbourhoods, parking lots and burger joints. Michael sports a zesty orange jacket to visit the Citrus Variety Collection and learns the difference between a pummelo and a papeda. Alongside oil, the citrus fruit industry, he discovers, is one of the bedrocks of the state's economy. At Laguna Beach, Michael learns how artists from the east coast travelled west on the Transcontinental Railroad to found a colony of 'plein air' painters attracted by the beautiful coastline and glorious light to paint outside.

• Michael Portillo