Last updated at 11:34

Lasers uncover hidden ancient Angkor Wat cities in Cambodia

Remains of huge ancient cities are discovered using special laser equipment near to the famous Angkor Wat temple site in Cambodia.
The temples of Angkor Wat in Cambodia, south-east Asia, were built around 900 years ago. Archaeologists thought they'd uncovered most of the remains of the ancient civilisation that once lived in the area. But now that's all changed...
Angkor Wat temple in Cambodia
Deep beneath nearby forests they've discovered the remains of huge cities that they didn't know anything about. Some of them are as big as New York City and could have been part of the largest empire on Earth at the time.
Images from the laser equipmentDamian Evans/CALI
Special laser scanning technology - known as lidar - was fitted on to the bottom of a helicopter. It was then flown over the nearby jungles and captured images of what's beneath.
Laser equipment being mounted on to the helicopterFrancisco Goncalves
It showed the remains of huge cities with houses, waterways and gardens within them. They were discovered by scientist Dr Damian Evans with help from APSARA, which looks after the area around Angkor, and the Ministry of Culture and Fine Arts in Cambodia.
Image of remains of huge citiesDamian Evans/CALI
Angkor Wat is a huge tourist attraction in Cambodia and is so famous in the country's history that it appears on the national flag.
Cambodian flagGetty Images
Experts say these are the most important discoveries made in recent years and change their understanding about the ancient Angkor civilisation and how they built and lived in their cities.
Ruins at Angkor WatAP