Kamala Harris makes history as she formally accepts the Democratic nomination for Vice President of the United States, becoming the first Black woman and first Indian-American on a major party's ticket. Christiane Amanpour speaks to Carol Moseley Braun, the first Black woman to become a U.S. Senator, about Harris' inspirational message and breaking down boundaries in American politics. Then, Pramila Jayapal was the first South Asian American woman elected to the U.S. House of Representatives, on the same night that Harris achieved that same milestone in the Senate. They discuss America's changing attitude towards immigration and the push for Medicare for All. Photographer Tyler Mitchell was just 23 when became the first Black photographer to shoot the cover of Vogue’s famous September issue, photographing none other than Beyoncé. He explains why he sees black beauty as an act of justice and his new book “I Can Make You Feel Good". And our Michel Martin speaks to Michael Chertoff, former Secretary of Homeland Security, about what he thinks are the greatest threats facing U.S. security, and how the role of the DHS has changed in recent times.