A portrait series made with Lego pieces recreates the 43 faces of the children who disappeared in Mexico’s mass student kidnapping of 2014. In the same gallery, a Ming dynasty temple stands like an ancient skeleton, uprooted from its native land. In his latest conceptual work, which includes a documentary film, Ai Weiwei, the Chinese artist and intellectual dissident, sees haunting reflections of China’s violent past in present-day Mexico. —C.J.F.