UNESCO is the United Nations Educational, Scientific, and Cultural Organization. It was involved in the moving and restoration of many temples in Egypt after the building of the Aswan High Dam.
The dam created Lake Nassar, which would flood many miles of the Nile south of Aswan and in the process, bury forever many of the tombs and temples of Nubia. UNESCO was asked to aid in the rescue of these temples in 1959 and as a result they began the enormous process of deconstructing, moving, and reassembling these temples above the waterline. UNESCO coordinated the Egyptian, Sudanese, and American efforts to save the monuments -- most notably, Abu SImbel, and the temple complex at Philae.
Work on the dam began in 1960 and initial dismantling and reconstruction of the Temple of Kalabsha began in 1961-3. The tiny temple of Beit-El Wali were also moved during this time.
The most impressive project, moving the two temples of Abu Simbel, began in 1963. The reconstruction of the temples at Philae did not finish until after the completion of the dam in 1969.
UNESCO has a very interesting timeline of the project here.
The following monuments were threatened and moved by UNESCO (from here):
- The small temples of Debod, Qertassi and Taffa, from the same period as Philae,
- the large temple of Kalabsha, built by Augustus to the local god Mandulis,
- the temple of Beit el Wali in vicinity of Kalabsha,
- the small Dendur temple further South,
- the rock temple of Ramses at Gerf Husein,
- the Dakka temple dating from the Ptolomaic times,
- the Roman period temple of Maharraqa,
- a temple of Ramses II at Wadi es Sebua,
- an old temple, built under the reign of Thutmosis III and Amenophis II (15th c. BC) at Amada, situated 205 km south of Aswan,
- the rock temple of Derr on the opposite, right bank of the Nile, dating to the period of Ramses II,
- a rock-cut chapel of Thutmosis III at Elleysia, just north of the fortified village of Qasr Ibrim, an important political centre in Roman times and later,
- the two rock temples of Ramses II at Abu Simbel, 280 km to the south of Aswan
- the small rock-cut chapel of Horemheb (end 14th c. BC) at Abu Oda on the opposite bank of the Nile, near the big fortified town of Gebel Adda (Roman and later).
The temples were dismantled (cut into large chunks for transport) and reassembled in groups on higher ground -- the temples of Philae were moved to a new island that was reshaped to match the original, and the temples of Abu Simbel were set into a completely man-made hill made of concrete.
UNESCO was also involved in creating the Nubian Museum in Aswan (a lovely museum!) for the treasures of southern Egypt.