Memories of the Children’s Crusade. A vision of alien visitations in the future. Invocations of superheroes. Fist-raising calls for change. These were all part of the 28th annual Z Experience Poetry Slam on Monday, part of the Yale Peabody Museum’s celebration of Dr. Martin Luther King Jr.‘s legacy of social and environmental justice. It capped two days of free events at the Peabody’s facilities and the New Haven Museum