In 2018, 60,000 uncharted structures were revealed in northern Guatemala by archaeologists with the help of Lidar technology lasers. The project applied Lidar technology on an area of 2,100 square kilometers in the Maya Biosphere Reserve in the Petén region of Guatemala. Thanks to the new findings, archaeologists believe that 7–11 million Maya people inhabited northern Guatemala during the late classical period from 650 to 800 A.D., twice the estimated population of medieval England. Lidar technology digitally removed the tree canopy to reveal ancient remains and showed that Maya cities, such as Tikal, were larger than previously assumed. The use of Lidar revealed numerous houses, palaces, elevated highways, and defensive fortifications. According to archaeologist Stephen Houston, it is one of the most overwhelming findings in over 150 years of Maya archaeology.