The brutalization and oppression of women living under ISIS is almost without parallel, from widespread rape and trafficking to forced marriage and murder. Female captives, including thousands of Yazidi women and girls, are sold as slaves in modern day slave markets. One U.N. official described meeting with a woman in ISIS-occupied territory who was forced to marry 15 different men in 1 year. Some of these so-called "marriages" lasted only 3 days. That is life under ISIS for these women today. Much of this seemingly crazed and indiscriminate violence against women is in fact a sinister and quite calculated strategy that goes to the heart of ISIS's survival. By forcing local women to marry into ISIS, the group expands its demographic base while reducing the population of those diverse communities it seeks to eradicate and to replace. Simply put, ISIS needs women-needs to control them-to establish its "caliphate" and give rise to the next generation of ISIS.