When Michael King Jr. was born on January 15, 1929, in a two-story house in Atlanta, the city had 715,000 residents. (His father changed his son’s name to Martin Luther at age 5.) Today, more than 6 million people live in metro Atlanta, a sprawling urban area that spans several counties. Between 2010 and 2019, that metropolitan area added more than 730,000 people, making it one of the fastest-growing cities in the United States, according to Census Bureau data.