Cities XXL is the sequel to Cities XL. It received a lot of criticism for being an only slightly improved version of the prior game and still containing bugs that existed in Cities XL.
The game’s creators, Focus Home Interactive, wanted to release a game with huge maps, capitalising on the disquiet that arose when SimCity was released in 2013 with relatively small city maps.
Cities XXL enables you to control both the micro and macro within your city and contains over 1000 unique buildings providing lots of diversity for you metropolises.
It is in no way related to the similarly titled (but better reviewed) Cities: Skylines.