Lombrives is one of the largest accessible caves in Europe, with kilometres of galleries cut through the limestone south of Tarascon. The tourist visit takes in vast chambers, columns and curtains of calcite, and a "cathedral" big enough to hold concerts. Longer adventure tours go deeper for those willing to scramble.
The standard tour starts with a short ride on a small electric train that saves the steep climb to the entrance. Inside, the cave is genuinely huge — colder and emptier than Niaux, with less art but far more geology. Sensible shoes and a warm layer are essential.