Between a rock and a hard place

“Levitated Mass” is a 456-foot-long concrete slot, over which sits a 340-ton granite boulder. As visitors walk through the slot, the pathway descends to 15 feet in depth, running underneath the boulder before going back up.   (Mel Melcon / Los Angeles Times)

Artist Michael Heizer, 67, conceived the work 43 years ago.  (Mel Melcon / Los Angeles Times)

The pyramidal stone has been cut across the bottom to fit heavily ribbed steel shelves. Thick bolts anchor it in place.  (Mel Melcon / Los Angeles Times)

A notched gray channel of polished concrete slices 456 feet across an empty field at LACMA. The channel, descending to a depth of 15 feet, is a two-rail pedestal for the huge stone megalith, which is bolted to steel shelves affixed to the center of each side wall. The path slopes gently down, inviting passage.  (Mel Melcon / Los Angeles Times)

Artist Michael Heizer signed his name along with his dog’s paw print in a plaque located next to his “Levitated Mass.”  (Mel Melcon / Los Angeles Times)