Saint-Jacques Tower (Tour Saint-Jacques) . This 52-metre (171 ft) Flamboyant Gothic tower is all that remains of the former 16th-century Church of Saint-Jacques-de-la-Boucherie ("Saint James of the butchery"), which was leveled shortly after the French Revolution.
In 1824 it was used as a shot tower to make small shot (a shot tower is a tower designed for the production of small diameter shot balls by freefall of molten lead).
A statue of Blaise Pascal is located at the base of the tower, commemorating the experiments on atmospheric pressure, though it is debated whether they were performed here or at the church of Saint-Jacques-du-Haut-Pas. A meteorological laboratory is also installed at the top of the tower.