Pont au Change in Paris

You're standing at the Pont au Change, the bridge linking the Île de la Cité to the Right Bank of the Seine. On one side you've got the Conciergerie and the Palais de Justice, on the other the Place du Châtelet. Take a look at the sides of the bridge. See that big letter N? That's for Napoleon III, not his more famous uncle. The bridge was built during his reign, between 1858 and 1860.