Mexico also made its official debut at the Venice Biennele, renting a labyrinthine Gothic palazzo near the Rialto Bridge that looks like something out of a Tolkien fever dream, with a high interior courtyard flanked by a winding stone staircase. The exhibition, by Rafael Lozano-Hemmer, is the opposite of the don’t-touch art that fills most of this city. Every piece requires some kind of participation.