In 2017, a painting of Jesus Christ holding a crystal orb became the world's most expensive painting when Saudi Arabian crown prince Mohammed bin Salman (MBS) paid $450 million for the piece which was auctioned off by Christie's in London. MBS purchased the painting based on its attribution to the Renaissance painter and all around genius, Leonardo da Vinci. But did Leonardo actually paint this picture? Maybe, maybe not. Authenticating Old Masters paintings is not a perfect science and, especially, if 500 years of the painting's history is missing. Through exhaustive research, art critic, documentary film maker and visiting fellow at the Warburg Institute in London, Ben Lewis, has tracked down its complicated journey. In his book, "The Last Leonardo - The Secret Lives of the World's Most Expensive Painting", he not only discusses the Salvator Mundi but he exposes the questionable world of the upscale art market, a world that operates mainly in secret and, in many respects, at arm's length from actual art itself. Join journalist Ernest Granson in conversation with Ben Lewis.