The Station Biologique de Roscoff is one of Europe's most important marine biology research centres, founded in 1872. The facility sits right on the waterfront and has been a centre for oceanographic research ever since, with the surrounding waters providing a rich laboratory for studying Atlantic marine life.
The public aquarium attached to the station offers a look at the sea creatures of the Breton coast: crabs, sea horses, lobsters, rays, and the kinds of fish that end up on local plates. It's modest by modern aquarium standards but well done and genuinely educational. Children enjoy it, and the setting — in a genuine working research institution — gives it an authenticity that purpose-built attractions often lack.