The iconic I Want To Believe poster was made popular by The X-Files television series. The character Fox Mulder (David Duchovny) had the poster above his desk. Mulder was a believer in UFOs as well as a US government conspiracy to cover up their existence. The second X-Files film was sub-titled 'I Want To Believe,' a reference to the poster.
Different versions of the poster were shown in the series but all were similar, showing a UFO flying or hovering above a forest of trees.