Cartoon Network "City" (partially lost bumpers; 2004–2007)
In June 2004, Cartoon Network debuted an updated version of its original logo (with the checkerboard motif retained and the "C" and "N" being the centerpiece) and a new slogan, "This is Cartoon Network!" The bumpers introduced as part of the rebrand, produced by Animal Logic, featured 2D cartoon characters from its shows interacting in a CGI city composed of sets from said shows.
During April 2006, there was a revamp of the CN City look using flat, dark, psychedelic colors, and a male announcer replacing the previous one (Nikki). This was presumably done to go along with Cartoon Network's "YES!" campaign they were running at the time, featuring characters from their shows acting out behind a red background. These updated City bumpers continued until June 2007.
While many of these bumpers are available on the Internet, several of them have yet to be found. The 2004-06 bumpers are fairly common, whereas the 2006-07 ones are comparatively rare. It is unlikely that they will all ever be found, as there are hundreds of them floating around.