Vatican is 2.3 times larger than Boston Common.
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: 0 km2 calculated
Boston Common is a central public park in Boston, Massachusetts. It is sometimes erroneously referred to as the "Boston Commons". Dating from 1634, it is the oldest city park in the United States. Wikipedia