With its 85 meters high and 289 steps, the church of Saint-Pierre de Sales overlooks not only but especially Marennes basin.

Listed since 1840 on the list of historical monuments, the church has undergone many changes over the centuries. Founded in 1047, then rebuilt in the 14th and 15th centuries, permanently replaced by that which currently exists, the church welcomes visitors every day.

The bell tower is itself open to visitors every day during July and August, from 10am to 12h30 and 14h to 19h, and by appointment off-season.

The church is named after the former name of Marennes: St. Peter (patron saint of fishermen) and the seat of the lordship, hence the name of Saint-Pierre de Sales, which has absolutely nothing to do with production of salt suitable for the whole region and which has benefited Marennes until the late Middle Ages.

A frigate of the Second Empire (dating is estimated in the second part of the 19th century) is preserved within the church. The ship is armed with 44 guns divided into two half batteries aligned to port and starboard. The name of the ex-voto is the "St Peter". It features the national flag at the gaff and mizzen door in the front two white stripes symbolizing the warships of the Second Empire.