Photo - Grotte des Portes de la Nuit
© SCHALK Patrick · CC BY-SA 3.0, https://creativecommons.org/licenses/by-sa/3.0/ · Grottocenter: Topo en plan des Portes de la Nuit · https://grottocenter.org/ui/documents/143884
Contains information from Grottocenter (Wikicaves), grottocenter.org, made available under the Open Database License (ODbL 1.0, https://opendatacommons.org/licenses/odbl/1-0/), modified. · The derived data is available on request under the ODbL: [email protected] · data as of 2026 · Source: Grottocenter (Association Wikicaves), worldwide collaborative cave database (grottocenter.org), modified. CC BY-SA 3.0, https://creativecommons.org/licenses/by-sa/3.0/ Grottocenter (Wikicaves) · Text by Frédéric Urien (La galerie du courant d'air), Frédéric Urien (Zone d'entrée et première partie), Frédéric Urien (La galerie des Bleus), Frédéric Urien, Frédéric Urien (Accès saisonnier) · https://grottocenter.org/ui/entrances/10023 · data as of 2026