Ahu Tongariki is the largest Ahu in Easter Island, which has fifteen Moai on its one hundred meters length of a basement. It was restored in 1990s by a co-project of Chile and Japan. Japanese crane manufacture, Tadano Ltd. , which donated a modern crane and funds, made it possible to rebuild Ahu Tongariki.
Tadano Ltd. site has descriptions of the project detail.
It started from Japanese TV Quiz show. This TV program introduces various life, culture, history, etc. from various countries of the world by quiz style. In November 1988, This quiz show was on-air and Easter Island was a theme on that day. On the program, former Governor of Easter Island was interviewed, and he said, "If we had a crane, we could save the Moai."
Some employee of Tadano was watching this program. This is the start of the Moai restoring project.
The project was supervised by University of Chile, and I found a description of it.
As a result of the devastating destruction of the tsunami, it was reasonable to believe that this great monument was lost forever. Since 1960, many colleagues had the dream of "restoring" the monument, but the complexity, time, effort and costs of such a project labeled the idea as impossible. In 1979, the authors systematically surveyed that section of the island, mapped the ruins of the area with great detail and also thought that a restoration was not feasible with the means, technical experience, personal knowledge of the materials and levels of information available at that time.
In 1991, this situation radically changed, and even though it was not a research priority and other important work was in progress, we started to consider the extraordinary possibility of rebuilding Tongariki. The donation, by a Japanese company (Tadano) of funds and equipment required, in particular a large modern crane capable of handling some of the largest statues allowed serious consideration of this project.
A modern crane donated from Tadano Ltd. was great help to restore Ahu Tongariki.