Napoleon III built two new railway stations: the Gare de Lyon (1855) and the Gare du Nord (1865). He completed Les Halles, the great cast iron and glass pavilioned produce market in the center of the city, and built a new municipal hospital, the Hôtel-Dieu, in the place of crumbling medieval buildings on the Ile de la Cité. The signature architectural landmark was the Paris Opera, the largest theater in the world, designed by Charles Garnier to crown the center of Napoleon III's new Paris.