The skylight over the rotunda of the Natural History Museum in Exposition Park has been nicely, if painstakingly, restored with help from the great-grandson of the original Judson Studios artist. But listen to some of the other work needed as part of the three-year rehab of the circa-1913 museum.

Inspections revealed cracks in the rotunda's outer dome as a result of shifting in the underlying concrete. That ultimately meant that the museum would have to remove the putty in between the individual ceramic tiles that sit on top of the concrete -- some 1,866,000 of them on the main dome -- and then inject an epoxy sealant between each of the 1-inch-by-1-inch pieces.

Crews also learned that all of the steel connections in the building are riveted together, not welded as is customary today....

The staircases leading up to the second floors of the north and south galleries, which had been covered by a gray carpet, were found to be made of battleship linoleum, an expensive material often found in old sea vessels, cars and floors. Workers will polish the linoleum to restore its original brilliance. Elsewhere, the museum is finding mosaics and marble walls that had been previously concealed.

Times story and photo gallery.

Cropped photo: Annie Wells / Los Angeles Times