Originally constructed in the 14th century and arguably one of the top sights in the city, Paks Margareta as she is known to locals, is 82m in diameter and boasts 5m thick walls. At one point, Tallinn's harbour was just outside the Great Coastal Gate and she certainly provided a formidable defence against any hostile forces trying enter the city here. The tower currently houses the Estonian Maritime Museum, see museum entry for details.