The world's first known water filtration system exists in the Mayan city of Tikal.
Date: 700
At its height in 700 CE, the city is home to 45,000 people. The climate in the area (in what is today known as northern Guatemala) has a dry season, so water for the city is stored in reservoirs. In the 2000s, archeologists will excavate zeolite, which is a volcanic mineral that captures microbes and does not naturally occur nearby, from the reservoirs, indicating that there was a system for purifying the water. Kornei (2020) will write that the Maya are "millennia ahead" of other civilizations in developing water filtration.