For example, the "fort Boyard".

It is a fortification located between the "île d’Aix" and "île d’Oléron". It was built in the 17th century. It is 61 meters long, 31 meters wide, and its walls are 20 meters high.
Under the Commune, the fort was converted into a prison, before being abandoned a few years later.
Since 1990, Fort Boyard has been used as the location for a television game show of the same name.
We can’t visit it but we can pass around with a boat.

Taken from : http://perso.wanadoo.fr/photo_france/gp17_charente_maritime.htm

...But the most interesting place when you are on holidays is the beach.

It is where you can sunbathe, walk on the beach, swim in the sea, and even do horseriding, which is the most pleasant sport to have a lot of fun..