Croatia is 520 times larger than Naperville, Illinois.
Area: 56,594 km2 World Factbook
Population: 4,470,534 (July 2014) World Factbook
Croatia, officially the Republic of Croatia, is a unitary democratic parliamentary republic at the crossroads of Central Europe, Southeast Europe, and the Mediterranean. Its capital and largest city is Zagreb. The country is divided into 20 counties and the city of Zagreb. Wikipedia
Area: 109 km2 calculated
Naperville is a suburban city of Chicago, located in DuPage and Will counties in the State of Illinois. Naperville was voted the second-best place to live in the United States by Money magazine in 2006. It was rated 1st on the list of best cities for early retirement in 2013 by kiplinger. Wikipedia