Cairo's Tahrir Square, once the staging ground for the massive uprising that ousted Egyptian President Hosni Mubarak, is quickly becoming notorious for something very different: an organized campaign of sexual assaults, activists say. The past year has seen an increase in attacks against women at demonstrations, but recently they have been particularly rampant—and, according to witnesses and activists, they have been following similar patterns. On the two-year anniversary of the revolution on Jan. 25, at least 19 women were sexually assaulted in and around Tahrir Square in one night, some with knives, activists said. Dozens more cases have been reported...