Showing the corbelled construction and the massive inner lintel over the entrance with its relieving triangle. Note in this picture the distortion of a wide-angle lens shows the top of the tomb to be leaning forward toward the entrance. In reality, it is located directly above the center of the floor circle. The entrance to the adjacent rock-cut chamber (off limits to visitors today) is visible with its own relieving triangle.
More about the Treasury of Atreus..