A vast stretch of medieval cities has been discovered near the Angkor Temple in Cambodia, hidden all this while under the country's tropical forest. Probably dating back nearly 900 to 1,400 years in history, the cities could be the world's biggest discovery yet, carrying the potential to rewrite the entire South-east Asian history. In an exclusive coverage by The Guardian, some of these cities could very well be the size of Cambodia's capital city, Phnom Penh.

The technology

The discovery was made in 2015 with the most extensive airborne laser scanner (ALS) ever used by archaeologists. Archeologists fired lasers into the ground from a helicopter to achieve an elaborate imagery beneath the forest ground. The study was conducted over a 1,901 km long area, the most recent analysis of which now hint that the cities could have constituted the largest empire on earth in the 12th century.

The findings

Large geometrical shapes were recorded that could have been gardens. The discovery also revealed detailed water systems that were perhaps built before the technology to build these was even invented.

Experts are now hopeful about finding answers to long-held questions that may "challenge" the Khmer dynasty's rise to power and decline in the 15th century. They strongly believe that this discovery could be the biggest one yet in history.