Tour sarrasine de Vitrolles
Tower in Vitrolles (Bouches-du-Rhône).
Each edition grades its towns against each other only.

Look within 5 km of its centre for the 4 places to visit; none is in Rognac. On the list: a fort, an attraction and a château, among others. The trip to Château d'If is 25 km.
After Tour sarrasine de Vitrolles come an attraction, a château and a museum.
Best known first: by how many Wikipedia and sister-site articles cover each place (Wikidata’s count). It isn’t a ranking of how good they are.
Out of town, most of the 4 are to the northeast.
The first 20 on the list, numbered as below. The shape is the commune of Rognac; the orange dot is its centre. © OpenStreetMap contributors · commune boundary: IGN
The list holds a fort, an attraction and a château.
Dark: in Rognac. Light: in the communes within 5 km of its centre.
You will find all 4 within 5 km of its centre.
Nothing is mapped in Rognac itself; these are within 5 km of its centre.
Château d'If (25 km) leads the 12 big names within reach.
AttractionChâteau d'If25 km south, in Marseille 7e
ChurchBasilique Notre-Dame-de-la-Garde26 km southeast, in Marseille 6e
AttractionCathédrale Sainte-Marie-Majeure24 km southeast, in Marseille 2e
MuseumMusée des civilisations de l'Europe et de la Méditerranée24 km southeast, in Marseille 2e
CathedralCathédrale Saint-Sauveur d'Aix-en-Provence18 km east, in Aix-en-ProvenceAttractionAttractionAqueduc de Roquefavour7.3 km east, in Ventabren
AbbeyAbbaye Saint-Victor de Marseille25 km southeast, in Marseille 7e
MuseumCamp des Milles12 km east, in Aix-en-Provence
MuseumMusée Granet18 km east, in Aix-en-Provence
MuseumMusée des Beaux-Arts de Marseille25 km southeast, in Marseille 4e
FortFort Saint-Jean25 km southeast, in Marseille 2eAttractionAttractionPont Flavien16 km west, in Saint-ChamasPlaces within 40 km of Rognac with an article in both French and English Wikipedia, nearest first.
Nothing is mapped in Rognac itself, but within 5 km there are Tour sarrasine de Vitrolles, Base Nautique, Château des 4 Tours and Tour Musée.
One, in town or within 5 km: Tour Musée.
The nearest with articles in both French and English Wikipedia: Château d'If (25 km), Basilique Notre-Dame-de-la-Garde (26 km), Cathédrale Sainte-Marie-Majeure (24 km), Musée des civilisations de l'Europe et de la Méditerranée (24 km).
From OpenStreetMap and Wikidata: named museums, galleries, châteaux, abbeys, gardens, zoos, theme parks and other visitor attractions whose mapped point lies inside the commune of Rognac, then those in the communes within 5 km of its centre, and well-known places within 40 km. Houses, ruins and gardens need a sign they’re open to visitors; places marked private, closed or disused are left out. The historic-monument link is the Culture ministry’s Mérimée record. A place that isn’t mapped isn’t listed, so this isn’t everything there is to see.
Sources: OpenStreetMap (© OpenStreetMap contributors, ODbL), Wikidata (CC0: descriptions, websites, Wikipedia articles), the Culture ministry’s Mérimée database (Licence Ouverte 2.0), IGN commune boundaries. Distances are from the commune’s centre point.
Photos from Wikimedia Commons, each under its own licence (our copy, resized).
Contains public sector information under the Licence Ouverte / Open Licence 2.0 (Etalab): INSEE, DGFiP, the Interior Ministry’s statistics service (SSMSI), the Ministry of Education (DEPP), the Health Ministry’s statistics service (DREES) and the Housing Ministry (Carte des loyers). Commune boundaries: IGN Admin Express.