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If the water seeps through the ceiling quickly,
若是水從洞頂滴落的速度較快
then the calcite is deposited on the floor of the cave, and that creates stalagmites.
方解石就會在洞穴地面上沉積，最后形成石筍。
Variations in water flow and air currents produce an infinite variety of forms,
水流和氣流的變化，造就了千姿百態的溶洞地形，
but all are created by the same process, the slow deposition of dissolved limestone.
但它們的形成過程都是一樣的，都是由水溶碳酸鈣緩慢沉淀而來。
And when stalactite meets stalagmite, a column is born.
鐘乳石與石筍相遇后便形成了石柱
Structures like these in North America's Carlsbad Cavern can take many thousands of years to develop.
北美洲卡爾斯巴德溶洞中的這些構造，經歷了數千年的形成過程。
But sometimes, the formations in a cave stop growing altogether.
但有時洞穴內的這些活動會完全停止
These flooded caves in Mexico have remained virtually unchanged for thousands of years.
墨西哥的這些水洞幾千年來幾乎保持不變
Since the last ice age, they've become cut off from the outside world,
自從上一個冰川期以來，它們便已和外界隔絕
yet their impact on life at the surface has been huge.
然而它們對地面上的生物卻有著極其深遠的影響
Five hundred years ago, they supported one of the world's great civilizations, the Maya.
500年前，它們維系著一個世界上最偉大的文明，瑪雅。
