How Do You Move a Whole Temple Carved Into a Cliff?

Why Were the Temples of Abu Simbel in Danger?

The two temples at Abu Simbel stand on the western bank of the Nile in southern Egypt, near the border with Sudan. The larger one was ordered by the pharaoh Ramesses II (also spelled Ramses) in the 1200s BCE, and its front is dominated by four huge seated statues of him [1]. Because the temples are carved out of the cliff itself, there is no building to lift off the ground. The rock and the temple are one piece.

In the late 1950s, Egypt was building the Aswan High Dam to boost its farming and electricity supply. The dam would hold back a giant reservoir, and the rising water would drown many ancient monuments along the river. Egypt and neighboring Sudan asked UNESCO, the United Nations agency for education, science and culture, for help [1]. For Abu Simbel, Wikipedia notes that the lake would have raised the water level there by up to 60 meters (200 feet), and that the sandstone would lose strength once submerged. That second point is from Wikipedia only [4].

UNESCO launched an international campaign on 8 March 1960. Around 50 countries took part, 22 monuments and building complexes were moved out of the water’s reach, and the total cost was about US$80 million, half of it donated [1][3]. Abu Simbel was the hardest case, because it was one carved mountainside. So what could be done with it?

Which Rescue Plans Were Considered, and Why Did Cutting Win?

Several ideas were floated in 1962. According to Wikipedia, the main ones were these [4]:

• Build a dam around the temples. A French firm proposed a curved concrete dam about 73 m (240 ft) high, with pumps to remove seepage. It was set aside over the risk of the drainage failing, high running costs and the worry that damp would slowly damage the stone. A related idea from British architects and an engineer was rejected because sandstone is porous and would eventually crumble in water.
• Lift the temples in one piece. An Italian firm proposed cutting each temple free, boxing it in concrete and raising it about 61 m (200 ft) on hydraulic jacks. Nothing that heavy had ever been lifted. The Great Temple alone was estimated at 250,000 tons. UNESCO announced this as its preferred option in June 1962.
• Cut into blocks and rebuild. The Swedish engineering firm VBB, which UNESCO had asked to oversee the project, worked on this plan. According to Wikipedia, Egypt adopted it in early June 1963 [4].

The block plan had a real risk. Sandstone is made of quartz grains that are only weakly joined, so cutting and lifting might crack the stone, with up to a third of the blocks possibly ruined. Even so, it had a realistic chance of finishing before the flooding and was estimated at about US$36 million, around half the cost of the others [4]. (Wikipedia is the only source I could read for this comparison of plans, so treat the details as one account rather than the last word.)

UNESCO’s own account is shorter: top experts, including hydrologists, engineers, archaeologists and architects, devised a plan in which temples would be dismantled, moved to higher ground and reassembled [1]. Once the plan was chosen, the next question was how to cut sandstone so carefully that the join would almost vanish.

How Was the Stone Cut Without Ruining It?

First, the cliff above and behind the temples had to go. Wikipedia says about 300,000 tons of rock were removed to free the temples. Excavators were used at first, then pneumatic hammers once vibration became a danger, and workers piled sand in front of the statues to protect them from falling stones [4].

Then came the delicate part. Before cutting, Egyptian workers spent seven months injecting epoxy resin (a strong glue-like plastic) into cracks and surface dents to hold the sandstone together. The saw cuts were planned to be only about 6.4 mm (a quarter of an inch) wide, so thin that the joins would be nearly invisible later. Most cutting inside and on the fronts was done with handsaws, including diamond-tipped ones, by Italian stonecutters working in cramped, dusty chambers at 38 °C (100 °F) or hotter. The contract capped each block at 20 tons for the inner rooms and 30 tons for the fronts. The cuts on the hidden outer side could be wider and were made with power saws [4].

The enormous faces of the statues of Ramesses were heavier than the 30-ton limit, so the crowns were cut off to make them lighter [4]. The first block was lifted out on 21 May 1965, and the last on 16 April 1966. In all, Wikipedia counts 1,036 blocks, and says none was seriously damaged [4]. UNESCO says slicing began in November 1963, using wire saws, and that “more than a thousand” blocks of about 30 tons each were numbered and moved to storage [1]. UNESCO says “more than a thousand” blocks and Wikipedia counts 1,036, which fit together, and the two accounts describe the same job (see the note at the end for the numbers that do differ). Each block got a code for its exact place, as if the whole temple were a giant puzzle. Now the puzzle had to be put back together on a new cliff.

How Was the Temple Rebuilt, and Where Did the Missing Mountain Come From?

The new site was higher and farther back from the river. UNESCO gives 64 m higher and 180 m inland, with an artificial cliff built for the reassembled temples [1]. Wikipedia gives 65 m higher and 208 m inland for the Great Temple. The numbers differ, but all sources agree the move was roughly 60 m up, so this note says only “about 60 m (200 ft) higher” [1][4].

Rebuilding started with the inner walls and ceilings. Joints inside were filled with a sand paste mixed to match the stone’s color, while the wider cuts at the back were filled with cement-based mortar. When the Great Temple was reassembled, Wikipedia reports an allowed error of only 5 mm either way for its orientation [4]. (I could not check exactly what was measured, so treat this as a rough sense of how precise the work was.)

The original temple had been inside a mountain, which carried the weight of all that rock. The rebuilt one had no mountain, so engineers built a concrete dome behind each temple so no weight rested on the carved rooms. The dome for the Great Temple was 55 m (180 ft) wide and 19 m (62 ft) high. Then about 300,000 tons of material from the original site was piled over the domes to make an artificial hill that closely matches the original setting [4].

The rebuilt complex was officially opened on 22 September 1968 [1]. According to Wikipedia, the project cost about US$41.7 million, roughly 10 percent over the first estimate, and about half came from Egypt and half from 48 countries [4]. That is a different number from the US$80 million UNESCO gives for the whole Nubian campaign, since the campaign saved many other monuments too.

Does the Sun Still Light Up the Inner Room Twice a Year?

One famous feature of Abu Simbel is that, on two mornings each year, sunrise light travels straight down the temple and falls on statues at the very back. The sun lights up three of the four statues, but the figure of Ptah, a god linked with the realm of the dead, remains in shadow. Wikipedia says the builders moved the temples with this alignment in mind, and a team checked it at sunrise on 22 February 1966, with another check on 22 October [4].

The dates given for this event vary. Wikipedia says 22 February and 22 October, but other writers give the 20th or 21st. Wikipedia also notes that the popular story that these dates mark the king’s birthday and coronation has no direct evidence, and that over 3,000 years the date must have shifted, and the move itself may have changed the alignment [4]. If you ever plan a trip for that sunrise, check with a local guide for the exact days.

Why Did Saving Abu Simbel Change How the World Protects Heritage?

The Nubian campaign did more than rescue temples. UNESCO says it put across the idea that heritage belongs to everyone, not only to the country it sits in, and that this idea led to the 1972 World Heritage Convention, the agreement behind the World Heritage List. In the middle of the Cold War, about 50 countries set their differences aside to take part [3][1]. UNESCO also says the campaign inspired later rescue campaigns in Italy, Pakistan and Indonesia [1].

Not every monument was cut apart. UNESCO says that with three exceptions, the threatened monuments in Egypt and Sudan were dismantled and moved. Another famous rescue was the Philae temple complex, which was relocated to a higher island between 1972 and 1979 [1][2]. Egypt also gave four temples to countries that had helped, including Debod to Spain, Taffa to the Netherlands, Dendur to the United States and Ellesyia to Italy [2].

Looking at photos of Abu Simbel today, you cannot see where the temple was cut. That, in the end, was the whole point of the 6.4 mm saw cuts.

Sources disagree on some numbers. The block count is given as “more than a thousand” by UNESCO and 1,036 by Wikipedia. Wikipedia also gives 807 and 235 blocks for the two temples, which add up to 1,042, so I left those figures out. The distances and heights of the move also differ slightly, as noted above.

How Can You Look Into This Yourself?

• Find photos of the front of the Great Temple and look for the joints. Can you find any?
• Think about a heavy piece of furniture. Would it be easier to move whole or in numbered pieces? What would you need to label?
• Read the UNESCO page “Working Together: Abu Simbel” [1] beside the Wikipedia section on the relocation [4], and list every number that differs.

Sources

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