John Green, left, pauses at the monument for his daughter at the dedication of Christina-Taylor Green Memorial Park in Tucson on Sunday. The Green family, Pima County officials, donors and friends celebrated the opening of the park at North Shannon and West Magee roads. Green was the youngest person killed in the Jan. 8, 2011, shooting that wounded then-Congresswoman Gabrielle Giffords. See more photos at tucson.com/gallery