The most venerated site in the Christian world, the tomb today consists of a limestone shelf or burial bed that was hewn from the wall of a cave. Since at least 1555, and most likely centuries earlier, the burial bed has been covered in marble cladding, allegedly to prevent eager pilgrims from removing bits of the original rock as souvenirs.

When the marble cladding was first removed on the night of October 26, an initial inspection by the conservation team from the National Technical University of Athens showed only a layer of fill material underneath. However, as researchers continued their nonstop work over the course of 60 hours, another marble slab with a cross carved into its surface was exposed. By the night of October 28, just hours before the tomb was to be resealed, the original limestone burial bed was revealed intact.

“I’m absolutely amazed. My knees are shaking a little bit because I wasn’t expecting this,” said Fredrik Hiebert, National Geographic’s archaeologist-in-residence. “We can’t say 100 percent, but it appears to be visible proof that the location of the tomb has not shifted through time, something that scientists and historians have wondered for decades.”