Fifty years ago, Arte Povera pioneer Jannis Kounellis opened an exhibition in Rome’s l’Attico gallery, intending to shock. Visitors were greeted by 12 living horses. They were tethered to the gallery’s walls and eating hay. Now, 50 years later, American artist Lara Nickel rides back in time: her first European solo show is an homage to Kounellis. In this exhibition, 12 life-size portraits of horses serve as an equine labyrinth for visitors to navigate. —E.C.