The western breakwater (Westdam) prevents the navigation channel to the port of Ostend from silting up. You can enter this artificial dam as a pedestrian or cyclist in favorable weather conditions. Highly recommended: you actually imagine yourself in the middle of the sea and you have an astonishing view of the coastline. At the very end you will find a pleasant 'work of art' where you can immortalize your presence in an appropriate way.
The western pier (Westdam) keeps the entrance to the harbor of Ostend clear. Pedestrians and bikers are allowed to pass to the end if the meteo is not too bad. At the end of the pier you'll find a nice attribute to make a traditional picture. The sight of the Belgian coastline is fantastic when you're on the pier.