DW Griffith's answer to the outcry over The Birth of a Nation was this long, at times heavy-handed, illustration of the results of intolerance in four periods of history: Ancient Babylon, Judea in the time of Christ, 1500's France and the present (read 1910's) time. Each story shows a boy, a girl and how their relationship is damaged by intolerance.
Griffith's work was ground-breaking in its time, and is still the film that modern moviemakers can point back to as helping to bring cinema out of its infancy. The Babylonian sequences are lush, the costumes detailed, and Constance Talmadge as the Mountain Girl is easily the best of the bunch. If you thought feminism started in the 60's, watch her and be educated.
Interestingly, the male and female protagonists aren't named. Our modern story showcases The Boy and the Dear One. 16th-century France's couple are called Brown Eyes and The Mercenary. In the Babylonian sequences, the Mountain Girl loves Belshazzar, but is loved by the Rhapsode. The Judean tale is one of Christly love.
Anyone interested in learning about film, or film history should take the three hours to watch this movie, and then watch it again. It's a labor of patience for modern eyes, but worth it.