The top photos of the day by AP photojournalists

Former President Barack Obama formally opened his presidential center in Chicago on Thursday with a call to defend democracy. He and Michelle Obama spoke as three other former presidents and their first ladies joined the Obama family on stage in an extraordinary event featuring politicians, A-list celebrities, athletes and other internationally known figures. Obama voiced his support for character, honesty, integrity, kindness, compassion and sense of duty, praising both Democrats and Republicans for their values. President Donald Trump was conspicuous both in his physical absence and by not being mentioned by any of the speakers or performers. Stevie Wonder closed the show with a rousing rendition of “Higher Ground."