Each edition grades its towns against each other only.
Of the 6 places to visit in and around Houlle, 4 are châteaux or heritage sites. None of them is inside Houlle itself. A longer outing takes you to V3, 30 km off.
Next to Blockhaus d'Éperlecques, the best known are 2 châteaux, an abbey 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.
Most of the 6 close by lie to the northeast.
The first 20 on the list, numbered as below. The shape is the commune of Houlle; the orange dot is its centre. © OpenStreetMap contributors · commune boundary: IGN
Count 4 châteaux or heritage sites and 2 museums or galleries.
Dark: in Houlle. Light: in the communes within 5 km of its centre.
All 6 on the list lie within 5 km of its centre.
Second World War bunker complex in the Pas-de-Calais department of northern France, built by Nazi Germany between March 1943 and July 1944 to serve as a launch base for V-2 rockets directed against London and southern England.
Nothing is mapped in Houlle itself; these are within 5 km of its centre.
The standout of the 12 is V3, 30 km from town.
CathedralCathédrale Notre-Dame de Saint-Omer8 km southeast, in Saint-OmerAttractionAttractionCoupole d'Helfaut12 km southeast, in HelfautAbbeyAbbeyAbbaye Saint-Bertin8.3 km southeast, in Saint-OmerAttractionAttractionCap Blanc-Nez36 km northwest, in SangatteMuseumMuseumForteresse de Mimoyecques30 km west, in Landrethun-le-NordAttractionAttractionMont Cassel22 km east, in CasselTheme parkTheme parkDennlys Parc26 km south, in DennebrœucqAbbeyAbbeyAbbaye Saint-Winoc de Bergues26 km northeast, in Bergues
MuseumFort des Dunes34 km northeast, in LeffrinckouckeAttractionAttractionDuchesse Anne30 km northeast, in Dunkerque
MuseumCité internationale de la dentelle et de la mode de Calais28 km northwest, in CalaisPlaces within 40 km of Houlle with an article in both French and English Wikipedia, nearest first.
Nothing is mapped in Houlle itself, but within 5 km there are Blockhaus d'Éperlecques, Abbaye de Watten, Château d'Écou and Maison des Archers.
2 museums and galleries in town or within 5 km, including Blockhaus d'Éperlecques and Maison des Archers.
The nearest with articles in both French and English Wikipedia: V3 (30 km), Cathédrale Notre-Dame de Saint-Omer (8 km), Coupole d'Helfaut (12 km), Abbaye Saint-Bertin (8.3 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 Houlle, 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.