The Philippines is home to the biggest manufacturing zone in the world, with 10 percent of the population living in metropolitan Manila. Many manufacturers operate in the city, where it is easiest to ship manufactured goods to the rest of the country. Manufacturing facilities make everything from electrical components to clothing and machinery, while the provinces produce tobacco products, processed foods, and textiles. In addition to these industries, some residents still manufacture their own products at home.
The region's name originated from a plant called the whie-flowered mangrove. This plant, which grows abundantly along the marshy shores of Manila Bay, is the source of the city's name. In the mid-16th century, three rajahs ruled the area. Rajah Sulayman ruled the communities south of the Pasig River while rajah Matanda and Rajah Lakandula ruled the region north of the Pasig River. These men and women made contact with the sultanates of Sulu, Brunei, and Cavite.
A number of refugees and immigrants fled the city to seek refuge in the Philippines. In the early 1940s, the Japanese government sent a courier to the Philippines, delivering notice of an invasion. On January 2, 1942, the Japanese forces began marching into the City of Manila. Many of them fled the city, but not all of them had made it out alive. The wartime population increased by two-thirds.