Nausicaá is one of Europe's largest public aquariums and the premier attraction in Boulogne, drawing over 500,000 visitors a year and consistently ranked among France's most visited tourist sites outside Paris. The facility covers marine life from tropical reefs to the deep Atlantic, with tanks large enough to contain sharks, rays, and schools of large pelagic fish alongside the more familiar Mediterranean species.
The facility has a strong conservation and education mission — it is a research centre as much as a visitor attraction — and the displays on ocean pollution and fishery sustainability are surprisingly compelling. Allow two to three hours for a proper visit. The location directly on the seafront, a short walk from the ferry terminal, makes it the obvious first stop if you arrive in Boulogne by boat.