In 1546, when Michelangelo was in his seventies, he was given one of his most important jobs. The old St. Peter's Basilica had been partly demolished and a new one designed by Bramante. But many architects had worked on it and it was still just at the beginning stages. Michelangelo was made the architect. He immediately improved the plan, had important parts made much stronger, and designed a huge dome, taller than any other domes in the world. He died before it was completed, but he left drawings and models so that the next architect, Giacomo della Porta, could finish what he had started. The dome of St. Peter's Basilica still stands as one of the greatest monuments of Christianity, and as a symbol of the city of Rome.