"Carmen Sandiego Returns" is an app launched Thursday.

It has been 30 years since a certain iconic childhood villain first simultaneously taught geography, math, civics, and language arts while going on adventures and creating chaos. On Thursday Boston’s Houghton Mifflin Harcourt Co. brings Carmen Sandiego to the small screen, launching an iOS app version of the character who has starred in a long-running computer game and public television series.More →