City is the thematic title under which most Town-related System sets were released from 2005 and onward. There are numerous sets that are associated with Construction, Police, Fire, Emergency, Train, Airport, Transportation, Cargo, Traffic, Coast Guard, Farm, Great Vehicles, Mining, and Space. European catalogs featured another theme called City in the years 1999 to 2000, which was referred to as City Center in American catalogs.
Since around 2000, the Lego Group has been promoting "Lego Serious Play", a form of business consultancy fostering creative thinking, in which team members build metaphors of their organizational identities and experiences using Lego bricks. Participants work through imaginary scenarios using visual three-dimensional Lego constructions, imaginatively exploring possibilities in a serious form of play.