If you give a look at the previous photo, which shows a general view of the village of Saint Martin, you’ll notice that these impressive ruins stand exactly on the top of the small hill on the back of the port, by the tower bell.
Saint Martin church has had a lot of vicissitude due to the historical alternation of Protestant and Catholic influences and later with the French revolution, the church was closed then reopened, then partially destroyed and then rebuilt again, starting from 11th century until 18th century.
But I won’t bore anyone with an unrequested superficial lesson of history.
We might go to peep inside instead....