Fearing a revolt from the planters (who had the support of Reunion Island) which would have represented a direct threat on the agricultural activity, the English built five towers at strategic points on the West coast of the island. They were to help them protect themselves in the event of an invasion coming from the sea. These towers were erected in 1815 by the Royal British Engineers. The design is a reproduction of a tower in Cape Mortella, in Corsica, from where the English had been pushed away. The function of the Martello Tower of La Preneuse was to protect jointly with the tower, of Saline Pilot the whole bay of Black River, through cross fires.
The Martello Tower of Black River is the best preserved one on the island. It is made up of 60,000 (black) basalt bricks. It is 9 metres high, has a diameter of 9 metres for its solid foundation and of 8.50 metres for its terrace. The thickness of the walls is of 3.50 metres. Its hiding place is in the centre: an underground tank which can contain up to 17,000 litres of water. On the terrace two canons pointed towards the bay of Black River.
The Martello Tower was restored in 1992 thanks to associations such as ‘Friends of the Environment’ and ‘Raleigh International’. Salvage archaeology which was underway made it possible to find 800 objects. Since the year 2000, the Martello Tower became a museum. Inside, one can see weapons dating from the time of the English, wax statues and various utensils which offer a glance on Mauritian life two hundred years ago.