Stalactites and stalagmites are the most common speleothems. Stalactites are centimeter to meter in scale, hang from the ceiling, and grow toward the cave floor. Stalagmites grow from the cave floor upward and are commonly fed by water dripping from an overhead stalactite. The most common variety of stalactites is the tubular soda straw, which is characterized by a central hollow tube and a translucent wall structure. Stalagmite morphologies are mostly determined by the drip rate, with candle-shaped stalagmites fed by relatively slow drips and dome-shaped stalagmites fed by fast drips. These speleothems archive Earth’s climate changes from the Palaeozoic to the present.
