Watch the trailer
http://www.youtube.com/watch?v=ipiCUY-HRcU

Gigantic city in the centre of the map with subway railways, hotels, nightclubs, pubs, residences, beaches, hospital, university, cinema, large walking streets, port, etc...
Spawn Centre will help you with maps of railways and differents hoods.
Skytrain Railways will drive you to one of the 6 others stations out of the city (really far from it)
If you follow the red cubes from the city's port you will discover another village
Others surprises are waiting for you all around the map