[citation needed] During July and August each year, the population of La Baule increases dramatically with many Parisians staying for weeks and regular day-trippers from Nantes.At that time, the very unstable dunes were occupied only by customs officers, who gave them the name of Bôle, a term indicating an easily flooded maritime meadow.In the 1920s, Parisian businessman Louis Lajarrige designed the Bois d'Amour district at La Baule-les-Pins and formed an agreement with the railroad company to move the rails away from the seaside to ensure a direct access to the beach.[citation needed] During World War II, La Baule formed part of the protective stretch of coast leading to the nearby harbour city of Saint-Nazaire, home of one of the biggest U-boat stations that the Germans built.The Musée Aéronautique Presqu'île Côte d'Amour (MAPICA), located at the airport, maintains a collection of restored historical French aircraft in flying condition.