Protests continue to sweep US over the killing of George Floyd by Minneapolis police.A thousands have turned out in Washington DC and other major cities.And Derek Chauvin, the former Minneapolis police officer who pinned Floyd's neck with his knee before he died, appeared in court on Monday.It was the first time since he was arrested and criminally charged, Chauvin did not enter a plea, a step that usually comes later in Minnesota courts. In Los Angeles, hundreds attended an open-air memorial service honoring Floyd and demanding justice for those killed at the hands of police.And demonstrators are seeking to transform outrage over Floyd's death into momentum for reform of this justice system and its treatment of minorities