Who is often credited with creating the first feature-length film?

D.W. Griffith is often credited with creating the first feature-length film, primarily due to his pioneering work in the early 20th century, especially with the release of "The Birth of a Nation" in 1915. This film was groundbreaking in many aspects, particularly in its length, narrative structure, and the technical innovations it introduced, which laid the foundation for the modern feature film format. Griffith's work established key cinematic techniques such as cross-cutting and close-ups, which were crucial in developing film as a serious artistic medium. His contributions not only set a precedent for feature-length storytelling in cinema but also significantly influenced the narrative style and production techniques used by filmmakers in the years that followed.