The library which handles connections to the online database (CaravelNet) is closed-source, although the rest of the game remains open-source under the Mozilla Public License and a fully functional executable (minus the CaravelNet connectivity features) can be made with the released source.
New York City | Mexico City | Kansas City, Missouri | Kansas City | Salt Lake City | Quebec City | Oklahoma City | City of London | city | Vatican City | New York City Subway | Panama City | Kansas City Chiefs | Kansas City Royals | Sex and the City | Mayor of New York City | Atlantic City, New Jersey | Utrecht (city) | Cork (city) | New York City Ballet | Manchester City F.C. | Jersey City, New Jersey | New York City Opera | Guatemala City | Atlantic City | Quezon City | City College of New York | Ho Chi Minh City | Groningen (city) | Birmingham City F.C. |