Atlanta is 786 times larger than Vatican.
Area: 0 km2 World Factbook
Population: 842 (July 2014) World Factbook
Vatican City, officially Vatican City State, is one of the last six remaining absolute monarchies whose territory consists of a walled enclave within the city of Rome. It has an area of approximately 44 hectares, and a population of around 840. Wikipedia
Area: 346 km2 calculated
Atlanta is the capital of and the most populous city in the U.S. state of Georgia, with an estimated 2013 population of 447,841. Atlanta is the cultural and economic center of the Atlanta metropolitan area, home to 5,522,942 people and the ninth largest metropolitan area in the United States. Wikipedia