Longhena's Santa Maria della Salute (begun 1631) has been noted for its extravagantly ornate exterior and its superb site at the entrance to the Grand Canal. Especially theatrical is the work of Guarino Guarini in Turin. His Capella della Santa Sindone (Chapel of the Holy Shroud, 1667-94) astounds the observer with its intricate geometric forms derived from Islamic buildings in the unusually high dome. Aside from Bernini, the major architects of the later Roman baroque were Francesco Borromini and Carlo Rainaldi (1611-91). Together they designed Sant' Agnese (begun 1652) in Piazza Navona. The elegantly undulating facade of Borromini's San Carlo alle Quattro Fontane (1665-67) in Rome, with its convex and concave rhythms echoing those of the interior, might be called the quintessence of Italian baroque architecture.