This Qasr al-Haj is a circular structure built of rock, local bricks and gypsum and the only way in is through an arched doorway that opens into a dark tunnel.
Emerging from the dark is a jaw-dropping moment.
All around me the walls rose up three-storeys high. Small arched doorways to 114 storerooms studded the walls. Behind each palm wood door lies a space about five metres deep where each local family would stored all its grain and other agricultural produce.
Below ground level were more rooms especially designed for the storage of large terracotta jars of olive oil. This qasr was still in use until the 1950s.
It has stood here for about 800 years, protecting the community's crops from bad weather, thieves and pests. This one was once owned by a man of the magnificent name of As-Sheikh Abd-Allah ibn Mohammad ibn Hillal ibn Ganem Abu Jatla.
The locals would pay him a proportion of their stored crops in rent, which he used to fund improvements in the local village - possibly the mosque, in particular, as Sheikh Abu Jatla was devoutly religious.
Pulleys were used to haul stores up to the higher levels and a precarious set of steps still protrude from the wall which once provided access.
At harvest time it must have been a place full of bustle and gossip. When I was there some of the palm wood doors gaped like dark open mouths and the only sounds were the flapping of pigeons that had set up home in the empty rooms.
The modern-day caretaker made green tea for me in the traditional way - pouring a stream of liquid from a great height so that the tiny tea glass was topped with foam. Tea with a good head of foam is considered a sign of hospitality.
Further west, at Nalut, which perches on the top of a cliff, is another qasr. In this one however, storerooms also fill the central area. A narrow lane twists through the canyon of storage rooms, in some places ropes still dangle from pulleys far overhead.
Nalut has another less historic claim to fame. It probably has the highest concentration of Mazda utes per capita in the world. Almost all date back to the 70s, almost all are blue and most appear to be a triumph of willpower of the drivers over the ravages of time.
Doors are often held shut with wire while drivers swathed in robes and scarves crouch over the wheel, willing their trusty steeds on for a few more thousand kilometres.
