“I hate museums,” the French entrepreneur Édouard Carmignac said in 2018. “I want a living foundation.” Back in the 1980s he found it, an estate on the Île de Porquerolles, a perfect home for the modern art he was accumulating. In 2011 he bought that estate, recalibrated its Provençal villa with modern inflections, and created his dream foundation. Now, for its fourth season, the American curator Chris Sharp has collaborated with the Port-Cros National Park on the exhibition “The Imaginary Sea.” The theme couldn’t be more appropriate. Because the villa is located on an island, Sharp says, the idea to turn it into an underwater natural history museum was intuitive. It also strikes a powerful chord. The ocean, its size and depth, is a mystery of lyricism and drama, yet its preservation demands concrete action. “The impetus” explains Sharp, “is to project a hypothetical future in which many of these animals might no longer exist. What is presented here are fanciful approximations.” —E.C.