Try this for a quick starting point... 1. Create a cube, size and locate as follows: size x=100, y=36, z=20. Locate the cube at x=0, y=18,z=0 and check the positive button. 2. Create a cylinder, size and locate as follows: size - x=80, y=21, z=50. Locate the cylinder at x=0, y=0, z=0. Rotate the cylinder x=90, y=0, z=0 and check the negative button. Select both the cube and the cylinder and group them. Apply a stone material. There's a dark stone with light mortar in the standard Bryce Rocks&Stones material. Render, Voila!