Sixty miles square at high tide, with a circumference of nearly 50 miles, the Bassin d’Arcachon, a triangular body of tidal water on France’s Atlantic coast, is so physically impressive it takes time before you notice that what’s absent is almost as appealing. No big yachts, designer boutiques, beach clubs blasting music, or overbearing bling.

With its sea breezes, temperate climate, pine and oak forests, and, at its mouth, the Dune of Pilat—the tallest sand dune in continental Europe, an ever evolving, 360-foot-high, nearly two-mile-long natural wonder—the bassin is a contender for the most magical place in coastal France, where the bar for “phenomenal” is already set quite high.