Plans to “restore” Giza’s pyramid of Menkaure by recladding its facade with granite blocks have stirred up a monumental debate.

The available evidence, including original stones remaining at the base of the pyramid, indicates that the original “design intent” included polished Aswan granite cladding, more splendid than the extant, rusticated limestone that formed the structure’s core (both visible in the photo).

But should the pyramid be reclad? The question is a redux of the dilemma constantly facing preservationists. How sure are you of your assumptions regarding original design intent and appearance? And how far do you go in reversing the effects of time? Unfortunately, ancient landmarks don’t come with original drawings or specifications.

If you’re inclined toward a reclad of the pyramids, then consider the “Leaning Tower” of Pisa.

Presumably, the original design intent was a perfectly vertical structure. But straightening the tower (if possible), out of respect for the original intent, would negate its fame and attraction for tourists, making it the Tower of Pisa—just another campanile. Perhaps the wisest course of action was stabilization of the tower (conducted between 1993 and 2001) preventing it from becoming the Lost Tower of Pisa.

Grappling with the complex issues of preservation, stabilization, and restoration of historic buildings—especially when the evidence is incomplete—requires expert judgment. Fortunately, the buildings we restore may be renowned works of architecture, but they are not as far gone as the Leaning Tower or the Pyramids of Giza.