Place a 16-inch-long drill bit into the drill and put the bit into the center of one of the hollow cores of the concrete block and drill down into the stone about 4 or 5 ... long 3/8-inch steel ...

At 8,000 feet, on the central plateau of Ethiopia, stand 11 churches, each carved from a single, gigantic, block of stone. No bricks, no mortar, no concrete, no lumber, just rock sculpted into ...