A foiba (from Italian: pronounced [ˈfɔiba]; plural: foibe ['fɔibe] or foibas)—jama (pronounced [ˈja̟mə]) in South Slavic languages scientific and colloquial vocabulary (borrowed since early research in the Western Balkan Dinaric Alpine karst)—is a type of deep natural sinkhole, doline, or sink, and is a collapsed portion of bedrock above a void. Sinks may be a sheer vertical opening into a cave or a shallow depression of many hectares.
https://en.wikipedia.org/wiki/Foiba
A foiba (from Italian: pronounced [ˈfɔiba]; plural: foibe ['fɔibe] or foibas)—jama (pronounced [ˈja̟mə]) in South Slavic languages scientific and colloquial vocabulary (borrowed since early research in the Western Balkan Dinaric Alpine karst)—is a type of deep natural sinkhole, doline, or sink, and is a collapsed portion of bedrock above a void. Sinks may be a sheer vertical opening into a cave or a shallow depression of many hectares.
