Staring up at the houses that hang from the ledges of Cuenca is not the visitor's only disorienting moment.
In the middle of Spain, the Moors built a town on top of a mountain. As the mountain top wasn't big enough for their town, they built houses that hung off the edge down sheer cliffs, sometimes by as much as 12 storeys. They're still hanging there.

We drove up from Valencia, leaving the deep green of coastal orange groves, and on through La Mancha. In La Mancha, we got to see - nothing, not even a house, for miles amid the dry, red plains. If the Martians land, this is where they'll come, because it looks like home. Suddenly, we were in perilous, grey mountain passes with glimpses of azure lakes to one side. Then, just as suddenly, we were back on Mars - along with wheezing lorries and hundreds of cars racing to Madrid on the ruthlessly straight trunk road.

The approach road to Cuenca's old town is a far less monotonous five minutes; steep, narrow and winding, it sharpens a driver's concentration. Anyone not fully alert on the way in was soon shaped up by the freezing cold on the tiny plateau where cars were parked. A couple of Spanish women in full-length fur coats stamped quickly into a souvenir shop, and a few gypsies half-heartedly offered to be guides. Otherwise, it felt as if we had the dark, cobbled streets to ourselves.

The heavy buildings show a blank face to the maze of stepped alleyways around the mountain-top. The Moors liked it this way; so did their successors, the local branch of the Spanish Inquisition - the only chink in their armour was deep-set windows covered with ornate metal grilles. The feeling of wintry desolation did not leave us when we left the streets for the central cathedral. It was bleakly neglected, with thick dust on the choir stalls, and freezing. Altars and statues lurked in a sinister, dirty gloom behind iron bars. A sad, single chandelier lit beside them simply emphasised the darkness. The treasury at the rear holds two El Greco paintings in warmth and illumination, but the reason for the blatant neglect of the rest of the cathedral seemed a mystery in a town which relies so heavily on visitor's income.

There was no such neglect round the corner in the Spanish Museum of Modern Art. The collection is housed in one of the famous casas colgadas, the houses that hang off the mountain. The 25-year-old museum has a collection by "contemporary" Spanish artists, most of whom seem to have died in the Eighties. There are not many pieces here that would stop the world, but there are a few that make you pause. The ingenious layout of the museum exactly reflects the feeling of wonder that being inside one of these suspended houses provokes. There are views from the sudden, wide windows to induce vertigo in a steeplejack, winding staircases erupting from narrow corridors, and huge rooms where you think there should be stairs. You lose all sense of scale and position - are you up or down, left or right? Just when you think you must be deep inside the building, trundling along a row of small paintings, you walk past a window which abruptly reveals that you're hanging off a mountainside.

Although clever people tell me that the dominance of abstraction in Spanish art can be traced back to the influence of the Moors and their non-representational Islamic art, it nevertheless feels odd to come across such a defiantly modern museum in the ancient streets of Cuenca. The old town still feels as cut off as the Moors intended: unassailable, and rumoured to be full of off-putting devils.

A few nights later, 200 miles downhill on the Costa Blanca, we called in for a drink with a friend who runs a small, out-of-the-way bar. We were chatting quietly, the only customers, when the door flew open and a tiny, very brown, very bald man whirled in, drunk as a skunk, yelling greetings and dancing at the same time. He ordered up a vat of gin and continued talking - to us, I think, but the tongue was no recognisable form of Spanish. He vanished for a while and I thought he'd gone; then I heard loud laughter behind me. There he was, delighted with himself, cavorting the length and breadth of the dance floor. When we left, we noticed a battered car outside with Cuenca number plates.

We'd been only a few hours out of his town when "Cuencan" became a new word in our vocabulary, defining anything endearingly bizarre, charmingly insane. After meeting that character down from the hills on a bender, "to go Cuencan" was our code for slipping into unmanageable, exuberant drunkenness, the last stage of abstraction before collapse n

Cuenca connections

The closest airport to Cuenca is Madrid, 120 miles west, with Valencia (150 miles east) a close second. Iberia (0171-830 0011) has a fare of pounds 104 return from Gatwick to Madrid, while British Airways (0345 222111) charges pounds 114 return from Heathrow or Gatwick. Both airlines require a Saturday-night stay to qualify for these fares. Debonair (0500 146200) has no restrictions on its flights from Luton to Madrid, which start at pounds 104.70 return.

To reach Cuenca from Madrid, trains run from Atocha station and take around three hours.

The Spanish National Tourist Office in the UK is at 57 St James's Street, London SW1A 1LD (0171-499 0901; brochures 0891-669920).