(210 m.) to the base of the dam.
Yesterday's photo and today's photo show that the concrete was poured in blocks. The dam is not solid concrete. If the dam had been built with a single, continuous pour, it would have taken 125 years for the concrete to cool, and it would have cracked and weakened as it cooled.
As the concrete was poured in blocks, they used steel pipes in the concrete with river water, then ice water, to cool the concrete, then filled the pipes with grout when the concrete cooled and hardened. The dam contains 582 miles miles (9277 km) of cooling pipes and enough concrete to build a two lane highway from New York to San Francisco.
Check out an additional glimpse of photos of the beauty and mystery of Easter Island at Viva la Voyage!