Within the cavern of Aven Armand is the world’s greatest concentration of stalagmites, including a gallery of stone columns known as the Forêt Vierge (Virgin Forest). Colourful illuminations create an eerie atmosphere. The cave is accessed via a funicular that drops 60m into the gloom. Guided visits last about one hour. Combination tickets with the Chaos de Montpellier-le-Vieux canyons at Causse Noir are available.