The whole place ought to be plain as day from that height." Huldricksson, his blue eyes alert, nodded.

With the greatest difficulty we clambered up the broken blocks.
To the east and south of us, set like children's blocks in the midst of the sapphire sea, lay dozens of islets, none of them covering more than two square miles of surface; each of them a perfect square or oblong within its protecting walls.
On none was there sign of life, save for a few great birds that hovered here and there, and gulls dipping in the blue waves beyond.
We turned our gaze down upon the island on which we stood.

It was, I estimated, about three-quarters of a mile square.

The sea wall enclosed it.

It was really an enormous basalt-sided open cube, and within it two other open cubes.