An ancient Maya city might seem an unlikely place for people to be experimenting with proprietary chemicals. But scientists think that’s exactly what happened at Copán, an archaeological complex nestled in a valley in the mountainous rainforests of what is now western Honduras.By historians’ reckoning, Copán’s golden age began in 427 CE, when a king named Yax Kʼukʼ Moʼ came to the valley from the northwest. His dynasty built one of the jewels of the Maya world, but abandoned it by the 10th century, leaving its courts and plazas to the mercy of the jungle. More than 1,000 years later, Copán’s buildings have kept remarkably well, despite baking in the tropical sun and humidity for so long.
Source: Ancient Maya city was built with stronger plaster | Popular Science