The tower of Ligny (Turrignì in Sicilian) is an ancient coastal tower located at the western end of the city of Trapani, in the Tyrrhenian Sea. Its profile stands out over the sea and immediately suggests its ancient role as a watchtower, but the richness of the decorations add to this military building an unusual charm.
It owes its name to the prince of Ligne , as well as captain general of the Kingdom of Sicily , Claude Lamoral , who ordered its construction in 1671 to defend the city from the incursions of Barbary pirates . 
The tower stands on the rocks that represent the continuation of the ancient city, first called Pietra Palazzo .  
During the Second World War it was an important garrison for the Navy, as an anti-aircraft post. 
In 1979 it was restored . 
And in 1983 the Museum of Prehistory and the Museum of the Sea was established by Prof. Francesco Torre, now called the Civic Museum Tower of Ligny. 

On the ground floor there are some prehistoric finds and a marine archaeological hall. 
You can also admire helmets of the Montefortino type, dating back to the First Punic War (241 BC); as well as some anchors and amphorae of the Punic and Roman era; artefacts and tools in flint and obsidian dating back to the prehistory of Trapani and various artifacts between the Elimo period and the late Middle Ages.

The Civic Museum of Ligny Tower is managed by the association Euploia-Archeology and Cultural Heritage, which periodically organizes temporary exhibitions. 

From its terrace, which is accessed internally with a staircase, you can enjoy a wonderful view: the view offers glimpses of San Vito Lo Capo, Erice,  Marsala, Trapani and a suggestive cliff that divides the Tyrrhenian Sea from the Mediterranean Sea. While to the west you can see the Egadi islands and the small island of Formica.