Kevin Costner ensured women “dominate” his new Western as he believes they built the American frontier. The Oscar-winner, 69, has brought his latest epic film ‘Horizon: An American Saga’ to the ongoing Cannes Film Festival, which stars Sienna Miller, Jena Malone, Abbey Lee, Georgia McPhail and Ella Hunt, among a string of other female cast members. He said at the premiere of his movie on Sunday (19.05.24) about why the movie focuses on females: “It’s almost impossible to imagine a West without women, isn’t it? The West doesn’t carry on without women. “And they understand that they were basical…