The lecture examines the architectural activity of Bernardo Buontalenti, the inventive genius behind the court spectacles of the Grand Dukes. It covers his designs for fortifications, villas, and his role in the invention of gelato. The primary focus is his celebrated Grotta Grande in the Boboli Gardens, a masterpiece of Mannerist "caprice" that blurs the line between art and nature, foreshadowing the Baroque.