Fodor's Expert Review Ligne de Cerdagne

Affectionately called le petit train jaune ("the little yellow train"), this line runs from Bourg-Madame and La Tour de Querol, both easy hikes over the border into France from Puigcerdà (Bourg-Madame is the closest). The border at La Tour, a pretty hour-long hike from Puigcerdà, is marked by a stone painted with the Spanish and French flags. The carrilet (narrow-gauge railway) is the last in the Pyrenees and is used for tours as well as transportation; it winds slowly through La Cerdanya to the medieval walled town of Villefranche-de-Conflent, where it can also be picked up. The 63-km (39-mile) tour can take most of the day, especially if you stop to browse in Mont-Louis or Villefranche. The last section, between La Cabanasse and Villefranche, is the most picturesque. In low season the trains have infrequent and unpredictable timetables.