Later, where cavities had developed, the top portion of the limestone collapsed, leaving the water exposed in deep natural wells of green and blue, many of which are surrounded by luxuriant vegetation.
تتكوَّن شبه جزيرة يوكاتان من صخور كلسية مسامية اخترقتها مياه المطر في الماضي البعيد ووصلت الى التربة التحتية .‏