In Karst topography, a very large, flat-bottomed, steep-sided depression formed by the collapse of cavern roofs or sinkholes is known as a:

💡 Solution & Explanation

A polje is a large, flat-bottomed, steep-sided depression found in karst landscapes, formed by extensive solution weathering and the collapse of underground caverns. Features like cirques and eskers are glacial landforms rather than karstic solution features.