Discovery HD, a 24-hour high-definition channel owned by CTV Inc. and U.S.-based Discovery Communications, launched in Canada on December 19. It’s on free preview until July 2006, but an HD-capable TV and an HD set-top box are needed to receive the channel. The channel’s high-resolution digital TV programming covers topics ranging from science and technology to adventure and natural history. It launched with the broadcast of Journey to the Centre of the Earth, Alien Planet and Miracle Planet.