CHICAGO — Dozens of protesters broke through a security fence near the site of the Democratic National Convention on its opening day Monday as thousands took to the streets to voice their opposition to the war in Gaza. [time-brightcove not-tgx=”true”] Families with babies in strollers, students, elected leaders and others holding signs and flags joined the march to the United Center, where the convention is being held, to call for a ceasefire in the Israel-Hamas war.