What appeared at first sight to be a true circle eventually proved elliptical—a form of temple found at Marib, the ancient Saba and capital of the Sabæan kingdom in Arabia, and at the Castle of Nakab al Hajar, also in that country. [8] Its greatest length is 280 feet; the wall at its highest point is thirty-five feet above the ground, and fifteen feet at the lowest; its greatest base thickness is sixteen feet two inches, and its thinnest point is about five feet. In the structure of the wall one very noticeable feature is that the portion to the south-east is very much better built, and is both thicker and higher: here the courses are marvellously true, as if built with a levelling line, and the stones, of granite hammered into shape, are exactly the same size, whereas on the north-west side and in some of the interior walls, which are marked in a lighter colour on the plan, the courses begin to get slightly irregular, and the stones of unequal size, suggesting almost a different period of workmanship; but then there is no point where the good definitely ends or the bad begins, except at a short gap on the northern side, where the good wall would seem to have been continued more in a northerly direction, and the inferior wall to have been brought round to meet it. There are three entrances to this circular building. The principal one, only three feet wide, faces the hill fortress and the north. It has an odd curvature in it, constructed evidently true north, whereas all the other entrances are straight. Below this entrance runs a very substantial substructure wall, and the little space immediately inside it was covered with a thick cement, made out of powdered granite, out of which steps had been formed leading down to the various passages which converge here from the centre of the building. The presence of this concrete in use for flooring and steps in buildings constructed without mortar is interesting, showing that dry building was used not from necessity but from choice. The entrance to the north-west had been walled up, and we had to climb over a heap of stones to gain admittance until it was opened out. It is narrow and straight, and protected by two buttresses on the inside. The wall here is very inferior to what it is at the main entrance. There was also another entrance between these two, presumably merely a sally-port in the wall, the lintel of which had consisted of wooden beams, which had been burnt, and on their giving way the wall above had also fallen down.