The team of French and Egyptian archaeologists were on a diving expedition in the Nile River when they discovered the carvings in an area that was flooded when the Aswan High Dam was constructed between 1960 and 1970.
Before the flooding, there was a conscious effort led by UNESCO to record and transfer as many archaeological remains as possible from the region. However, lots of the artifacts were not able to be relocated in time and were soon taken under by the construction project.