Nature filmmaking has a long and mobile history, from its pre-cinematic roots in nineteenth-century photographic traditions to its current status as a genre found most commonly on television, and perhaps most spectacularly in large-format IMAX cinema. Now only rarely seen in conventional theatrical release, nature films have alternatively enjoyed significant popular presence and languished in obscurity. Despite the genre's uneven presence in theaters, its thematic occupations can be clearly periodized. From the earliest years of cinema through the 1930s, nature filmmaking most often took the form of expedition travelogues, in which flora appeared as terrain to be crossed over, and fauna as objects to be filmed, captured, or killed. Meanwhile, noncommercial scientific filmmakers developed techniques through which animal behaviors could be observed and recorded for scientific study. Post–World War II nature filmmaking returned with the animal as subject, the human rendered either invisible or on standby as steward of the most fragile facets of an invaluable environment. Near the end of the twentieth century, the genre, on screens small and large, proliferated in new forms, fusing readily with reality-based and fictional genres.