Photo - Birkelhöhle
© Babucke · CC BY-SA 3.0 DE, https://creativecommons.org/licenses/by-sa/3.0/de/ · Wikimedia Commons · https://commons.wikimedia.org/wiki/File:Birkelh%C3%B6hle-innen.jpg
Source: Geotopkataster Baden-Württemberg (Regierungspräsidium Freiburg – LGRB) (services.lgrb-bw.de), modified. Data licence Germany – attribution – version 2.0 (dl-de/by-2-0), https://www.govdata.de/dl-de/by-2-0 Datenquelle: Regierungspräsidium Freiburg - LGRB, www.lgrb-bw.de · data as of 2026 · 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. · length · obtained 2026-11-13 · https://grottocenter.org/ui/entrances/23572 · data as of 2026 · Source: Wikidata – cave items (Germany) (www.wikidata.org), modified. CC0 1.0, https://creativecommons.org/publicdomain/zero/1.0/ Wikidata (CC0 1.0) · data as of 2026 · The derived data is available on request under the ODbL: [email protected]