Why were the Abu Simbel temples in Egypt relocated in the late 1960s?

The two Abu Simbel temples were relocated in order to keep them from being submerged during the creation of the Aswan High Dam reservoir. Different plans were suggested to save the temples from submersion; ultimately the plan chosen was to relocate the temples to higher ground.

Relocation started in 1964, the temples were cut into large blocks and moved to a new location 65 meters higher and 200 meters back from the river. The project was completed in 1968.

The two temples, dedicated to several Egyptian gods were also monuments to Ramesses II and his queen Nefertari, were constructed in the 13th century BC. Originally carved out of the mountainside during the reign of Ramesses II over a period of about 20 years, their purpose was to impress Egypt's southern neighbors, and to reinforce the status of Egyptian religion in the region.