The dome

The Dome.
The way the ancients constructed domes is not understood.  It is solid geometry.  The arch stays up because all the stones try to fall in but are held up by the one below.  In the same way, in each ring of a dome the stones try to fall in, but are held up by the ones one each side.  A dome can be thought of as a series of layers that are held in laterally against the vertical force of their potential energy from raising the stones to that height.  They can be shaped radially to the centre of the sphere.  As they are constructed, they will tend to slip down during construction but can be held in place by iron cramps or physical keys like on bricks.  Once an entire ring is complete, they will hold themselves in place through their own weight, pushing sideways, and they will not need any iron ring or chain to hold them in place as was once thought when domes were reinvented in the renaissance.  The layers can also be corbelled out, so the new elements can be held by counterweights dring construction and then when the layer is complete they will again hold themselves up as a singular, circular element, with its separate elements held together by their own "weight". 

One of my imaginary Super-Buildings (buildings on a civic, not human scale) is the Great New Temple in Jerusalem.  I have always imagined an immense glass dome, made of long glass blocks in a geodesic pattern, held up on six intersecting concrete and stone arches in the form of three intersecting triangles.  It is to cover the whole of Jerusalem, centering on the top of Mount Zion, Temple Mount, where a hole at the very top of the dome, with a metal ring around it will be open to the sky why ligtnight can come through and light the fire on the top as must have happened thousands of years ago.  Lightning is quite common at certain times of year in the Judean Hills.  The building would appear like a huge Magen David from space, covered by an enormous glass dome.  It could be build.  At a smaller, but still large scale, it would be a genuine fitting Third Temple, that retains the wonderful architecture of the present Dome of the Rock as a Holy of Holies.  (I have been there and into the cave within the rock and it does feel "holy".)  That would provide six doors, two for men and women of both Jewish and Moslem faith and two for Xians, perhaps East and West.  The glass for the dome is just the sand of the desert poured into great moulds and fired at high temperature.  It is an ancient technology first discovered or invented or received in that area, now put to large-scale use.