Robert F. Sission/National Geographic Society

Measuring a Chapel Dome: American scholars record the diameter of one of the two domes in the Church of St. Catherine. Between the white-washed domes can be seen the iron roof of the Chapel of the Burning Bush; access to the traditional site of the Burning Bush is only through either of the two domed side chapels. Inside the church, flanking the pair of windows, are the two mosaics of Moses.