Getting the 900 lb. cement culvert that would serve as our firepit in place was quite the chore. I had to dig a 3 x 3 foot hole with one side curved outward for it to slide down into with the culvert resting precariously along that side on the edge.  Of course it didn't slide in straight so I had to dig more out all the way around it and shimmy it back and forth to get it positioned properly with the surface.  The process took about 4 hours.