Guam is 13 times larger than Manila.
Area: 544 km2 World Factbook
Population: 161,001 (July 2014) World Factbook
Guam is an organized, unincorporated territory of the United States in the western Pacific Ocean. It is one of five U.S. territories with an established civilian government. Wikipedia
Area: 42 km2 calculated
Manila is the capital and second largest city of the Philippines. It is one of the sixteen cities which, along with the municipality of Pateros, make up Metro Manila, the National Capital Region, whose overall population is around 12 million. Wikipedia