UPN was not the first "big six" network to pull children's programming: NBC became the first to remove kids shows entirely in August 1992, when the network launched a live-action block for teenagers called TNBC; children's programming returned to NBC in 2002, through a time-lease agreement with Discovery Kids. In the years since the block was discontinued, all other major broadcast networks, including UPN successor The CW, would gradually abandon children's programming by selling their respective children's blocks to Litton Entertainment, who produces primarily unscripted E/I content targeted primarily at teenagers, or in the case of Fox, removing children's programming entirely. Fox's sister network, MyNetworkTV, has never supplied children's programming as part of its lineup; both networks leave the responsibility of acquiring E/I programming to the affiliates, primarily through the syndicated block Xploration Station in the case of the former.