As early as 2,185 years ago, the Maya built the Corriental reservoir filtration system. This would mean that the water system was developed shortly after their settlement in the ancient city of Tikal, now in northern Guatemala. The system, which uses natural minerals, would still be as effective today. Other ancient water filtration systems have been found around the world, but it appears that the Maya were millennia ahead of other civilizations, using zeolite as a major component (,still used in today's filtration systems). This likely came out of necessity, as the water quality without filtration would have made these people very sick. This discovery adds to the long list of technological achievements of this civilization.