His last major commission for Urban VIII was for a fountain outside the family palace at Piazza Barberini. With the Triton Fountain, completed in 1642-1643, Bernini abandoned the staid, architectural format of earlier fountains to create a spectacle. Four dolphins, tails entwined around the papal coats of arms and supporting a giant bivalve, arise from a pool of water. The sea god Triton, seated in the middle of this great shell, blasts a stream of water heavenward from a massive conch shell. The base, basin and figure are integrated into an organic, poetic whole, which Bernini intended as a celebration of Urban VIII's rule.