On the northwest coast of Corsica, the island of Pietra - 'big stone' in Corsican - is the largest islet of the small archipelago facing the city of L'Ile-Rousse. It houses a lighthouse at its tip and is now connected to the port by a dyke. It retains remnants of the past such as a Genoese tower built in the 16th century to control the maritime invasions. Traces of ancient habitats were discovered in the 20th century during archaeological excavations.