After climbing the 116 steps in the Petit-Fort Philippe lighthouse (in July and August), you’ll find yourself 30 metres above sea level, with a breathtaking view of the banks of the river Aa.
Admire the mouth of the Aa, the Gravelines harbours, and Grand-Fort Philippe. A little further away, there’s Oye-Plage, with its long sandy beaches and bird sanctuary.
http://www.tourisme-gravelines.fr/fr/decouvrir/monuments-autres-sites/phare-petit-fort-philippe/