In honor of the country’s semiquincentennial, Sotheby’s presents “250 Years of American Art & Culture,” a celebration of American craftsmanship and design that takes in fine art, literature, craft, and ephemera. A convergence of themed auctions, exclusive content, and special programming, the summer event is complemented by “David Webb: Mavericks on Madison,” a selling exhibition of several extraordinary David Webb jewels making their public debut, including the Delacorte Suite, a rare late-1950s suite of aquamarines and diamonds; the Couture Coral Collar and Brooch, showcasing Webb’s bold use of carved coral; and the Emerald Cross River Ring, a significant emerald and diamond design never before photographed. These historic works are presented alongside contemporary creations, including David Webb’s Totem Necklace, debuted last year. Together, these pieces offer a rare opportunity to experience the house’s rich heritage and continued creative evolution. —Carolina de Armas