It has to be one of the world's more hallucinatory sights, these buildings grouped on the side of a hill, rising like a mirage through the blazing Saudi Arabian sun. From a distance it appears to be a small modern city of soaring skyscrapers, and yet the structures actually constitute nothing more, nor less, than a traditional village where ways of living, and methods of building, have hardly changed in 2,000 years.

We are given a privileged look at such villages, and other extraordinary manifestations of traditional Saudi architecture, in sensitive pencil drawings by Wahbi Hariri-Rifai, on view through Nov. 7 in the Smithsonian Castle. Hariri-Rifai, 70, is a distinguished architect who believes that after retirement "it is necessary to study, to do something with the life, and not just to sit." These drawings are the first fruit of his self-appointed assignment (accomplished with the full support of the Saudi Research and Development Corp.) to study and document that nation's architectural heritage.

Each of the towers in those villages in the fertile lands of Asir, in southwest Saudi Arabia, houses an extended family. Older family members reside on the top floors (sometimes as high as 12 to 15 stories above ground), and the more active middle and younger generations occupy the middle floors. Ground level is reserved for animals and, in the dark innermost rooms, for crop storage. The towers have tapering walls, which helps to account for their insistent verticality when seen from a distance. Up close, Hariri-Rifai says, they seem much more domestic in scale. The walls are made of baked mud, often articulated by regular, horizontal rows of projecting flagstones for structural strength and shade.

The 22 drawings in the show make up a fascinating short tour of the history of the Arabian peninsula. Scarcely less startling than the villages of inland Asir are the rock dwellings and tombs of Madain Salih in the northwest, near the Jordanian border. These structures, their classically detailed faces carved from solid stone hills in the first century B.C., reflect the wide-ranging influence of Greece and Rome, for they sat upon a thriving trade route between the peninsula and the Mediterranean world.

Later, African influences can be seen in the conical, thatched huts of coastal Asir, and imperial Ottoman influences are apparent in the mid-16th-century mosque in the Ibrahim palace in Hofuf. Ottoman culture is present, too, in the urban buildings in the old quarters of Jidda and Mecca, where four- to six-story structures, with stone fac,ades accentuated by projecting bays and carved wooden screens, are built right to the edge of bazaar-like streets.

Hariri-Rifai was born in Syria and was educated as an architect there and at the Ecole des Beaux Arts in Paris. His Beaux-Arts training shows in the enormous skill with which he draws and, indeed, in his whole "retirement" enterprise. A modern scholar might be content with photographs, especially in areas where mid-afternoon temperatures often rise beyond 110 degrees Fahrenheit, but Hariri-Rifai obviously believes that there is something more to be learned -- absorbed, really -- in the patient exercise of hand and pencil upon a blank sheet of paper.

This conviction is our good fortune, for the drawings combine an archeologist's respect for the facts with an artist's sensitivity to the spirit of a place. Happily, Hariri-Rifai is continuing his research, and plans a second, more comprehensive series of drawings to examine the structural details and uses of the buildings he so clearly loves.