Answer:

karst

Answer	Crossword Clue
KARST	Area likely to have sinkholes
KARST	Limestone rock formation
KARST	Limestone plateau on Adriatic coast.

KARST	Limestone region
KARST	Land formation known for its caves
KARST	Limestone cavern phenomenon
KARST	Limestone terrane
KARST	Limestone landscape
KARST	Eroded lime- stone terrain