Английская Википедия:Cupola (cave formation)
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A cupola is a recess, indentation, or cavity in the ceiling of a lava tube, a kind of cave formation.[1][2] Cupolas may originate from partial collapse of the ceiling, inflation of the roof by gas or lava pressure, or from a roofed-over site of a former tube overflow.[3] They can be situated anywhere in a lava tube but are most common in lower-level passages.[4]
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