When Montpellier was a fully fortified city, it was surrounded by a large wall and had twenty five towers around the edge that were used as vantage points and tools of defence. Today, only two remain, this tower and the Tour des Pins. In the 18th Century the magnificent stone structure was converted into an observatory for the National Science Society. A working facility, the tower is open to be viewed at all times and occasionally public entry is permitted inside.
