The photograph below shows the door of a building called a “bait al qufl” (house of locks) built for protection from the elements. The floor, a metre or so below ground, has raised stone slabs for eating, sleeping and storage. The recessed door has a double locking system and opens inwards, one does not get in without being asked!
When I first came across one of these while trekking on Jebel Harim; the door was not locked and the place seemed abandoned, so what a shock I had when pushing the door open and stepping from bright sunshine into the dark interior – I fell in! Luckily my camera was on a tripod and not in my hands.