IT'S one of those things you seem to do on vacation - climb ancient spiral staircases. I don't quite know why. It could be just because, like alpine peaks to rock climbers, they are there. But also, presumably, it's because this is about the only time you have time to climb ancient spiral staircases: In my experience, they generally go on (or rather, up) more or less forever.Ostensibly, of course, you climb them because there is promise of an outstanding overview of the entire urban setting spread out below you once you reach the top. But I secretly suspect that it's not the getting there but the means of getting there that really attracts. There is something about treading on worn stone steps that is immensely appealing. And there is something mysterious and exciting about moving slowly up through the inner structure of an old building - a close encounter with ancient fabric. It prompts imaginative evocation of centuries of past footsteps, this corkscrew adventure into the dimness. And there is something about staircases in general that strangely engages the feelings.... At its most basic, there is also a sense of challenge and achievement. In Munich last year, we found ourselves once again footing it spirally up a medieval tower along with more than a scattering of other intrepid, pseudo-mountaineering tourists. Part of the fun of this adventure is suddenly meeting, head-on, a large, enthusiastic family descending at high speed. Everybody goes into a kind of flummoxing fit trying to determine how to scrape past each other without inadvertently dislodging one or two people catastrophically from the narrow ledges. Once this tricky conflict of interests has been negotiated, it is then the positive duty of the down-goers to call behind them to the up-comers: "You've only 598 steps to go! Don't give up!" Though couched in terms of witty encouragement, what this really means is: "So, you think you've got the stamina to reach the top, huh? Who are you fooling!" It's this, well, competitive spirit, presumably, that inveigles mountaineers into ascending Mt. Everest even though, after all, it has been done before. On this occasion in Munich, my wife kept repeating every few octaves of the climb "To think that we paid for this!" This indisputable fact revealed the enigma at the heart of this particular touristic preoccupation: Who in their right minds would give away good money to subject themselves to such exhaustive effort? But then, of course, when you are on holiday you aren't exactly in your right mind. Having paid, however, doubly means no turning back. Anyway, I'm proud to report that we did reach the summit (unlike some others we encountered a third of the way up, resting in shock). We duly circumnavigated the vertiginous balcony, admiring the rooftops and trying to locate the airport. And now the descent. This event, one that's quicker, naturally, and rather dizzying, is also more fun because it's your turn to urge on struggling newcomers. Just as we sniffed daylight, almost at the bottom, we came upon an announcement that medals marking our heroic triumph as climbers-of-the-tower were here available. But upon investigation, we discovered that you had to buy them! I was struck dumb and my wife was struck vocal - both reactions signifying the same thing: "We deserve medals all right, but pay for them? They must be joking!" Clearly we had reached the point where exploitation had inflated itself into naked cupidity. Even willing victims have their limits. They could keep their medals. The more I come to think of it, stairs, staircases, steps indoors and out, truly are structures of great fascination. Especially as a child, I had dreams about various examples I knew well, so strong was their impression on me. There were some garden steps at my grandmother's in Norfolk which wound downward through overgrown shrubbery, dark and green, to a side gate onto the road. To a small child there were shadowy thrills to be fantasized here, and although obviously people had trodden them before, I always felt I was pioneering unknown territory descending these moss-green stones, the air oddly cold. At home in Yorkshire we also had outdoor stone steps, running down a bank through some trees. They reappeared in night dreams not because of their awesomeness, but because from the top of them I always took off on my various flights. I wasn't quite as adept at flying as an eagle, but by dint of vigorous sustained pumpings of the arms, I would lift off at last, and once airborne, there was no stopping me. I would skim down barely above the steps and then sometimes would fly high above trees and buildings; but mostly I would glide with the exuberant, exhilarating relish of the earth-free, about six feet up, straight along "Villa Road." I suppose I was recreating the sensation of cycling down that long straight road - which we were forever doing in sober daylight - but found it even more delightful wafted and soaring on air currents rather than wheels. INSIDE our house there were two main stairs, back and front. These also recurred in my dreams. The back stairs, in particular, were featured, possibly because I was immensely intrigued by an unusual and very tight space between the stairs and the tall window that lit them. It was as if the architect hadn't quite decided what do do with this gap, so he just let it be. Why it held my imagination, I can't say. Children are strange creatures. Having two stairs, which shared a common landing, was an invitation to games. My brother and I spent entire mornings, each barricaded with all sorts of furniture, pelting each other with trillions of dried peas across the landing, I in command of the front stairs, he of the back. I confess to gigantic, wild, and high-spirited enjoyment of the pea-fights at the top of the stairs. Naturally enough, stairs have stimulated architects' imaginations as structures that are more than merely functional - though far too often they have turned the rather simple need to rise comfortably from one level to another into extravagant visual effect, theatrical features displaying grandiosity and status, more suited to opera or Hollywood than real life. Some Baroque architects turned stairways into such fantasies - Vignola, for example - with such spectacular conviction that you can almost overloo k the showiness that motivated them. Michelangelo's remarkable stairs in the vestibule of the Laurentian Library in Rome have caused one writer, Howard Hibbard, to observe that with their conception "Michelangelo, almost single-handed, invented the use of the interior stair as a major sculptural feature of architectural design." Hibbard is not completely in favor of these stairs, though, calling them "bizarre," and "from a practical point of view, ridiculous." But they remain a work of an astonishing originality, promoting "the utilitarian stair into a major architectural element, strange, fascinating, and perilous." Three flights all lead ultimately to the same doorway - one main central staircase of oval steps progressively narrowing as they march up from the vestibule, and "wings" at each side of straight steps. Describing his idea for them in a letter to Giorgio Vasari in 1555, Michelangelo was trying to remember what he had first planned (but left unbuilt) 30 years earlier. "I recall a certain staircase," he wrote, "as it were in a dream." In a dream. That's the way a staircase worth its salt should originate... set loose, to a degree, from the dull pull of flat ground. Years ago I happened to be near the small city of Wells in Somerset. It was late afternoon, but I had for so long wanted to see something in the 12th-century cathedral that I thought it was worth a try. I banged on a side door, and someone appeared only to state that it was too late for visitors. I peeped over his shoulder through the doorway, but could not see what I was after. It was many years before, at last, I found myself inside the cathedral. I knew what to look for, and indeed, they more than lived up to my expectation. In the East End, leading up on the way to the 14th-century Chapter House, is the most magical and musical of stone staircases. It lifts the spirits. Writer after writer has tried to translate into words what these wide, worn steps, which have been molded into undulant sculpture by 600 or 700 years of shuffling feet, mean to them. Impossible! Some way up, the stairs divide in two directions, not like pathways, but more like dunes formed by water and wind. The shallow steps have an almost organic, or at least geologic, life of their own, not seeming like man-devised masonry at all. Their form is as natural as a hillside and seems almost to flow around the vertical walls and clusters of columns through which they climb up and off into a deceptively unending distance through an arched doorway and then on through another.... Earlier in their clim b, they wheel to the right in an arc and up with sudden steepness to the Chapter House itself. These stairs are not like something mathematically calculated, placed precisely onto and built up from a flat floor. They surge up with the integral logic of inevitable rightness as though describing the land underneath, like contour lines on a map. They seem almost to bodily lift up this Gothic building as they climb, bringing an inspired escape from dead level and dead horizontal. I KNOW of no stairs or steps to rival these, either in architecture or in the less functionally demanding realms of painting. In thinking about this subject, I have been amazed how often stairs have inspired painters to great originality - from William Blake's watercolor of "Jacob's Ladder" to Marcel Duchamp's famous emblem of modern art, "Nude Descending a Staircase," from a whispery, shadowy black chalk evocation of a 19th-century big-house backstairs in Xavier Mellery's "The Staircase" to Degas dancer s coming down an iron spiral in a rehearsal studio to the early work of the Italian Futurist, Giacomo Balla. Each of these works is resonant with the mystique, the dynamics, and the fascination of stairs. Balla's, a view from above down a deep well, with three women pausing to look up as they go down, is simply called "The Stairway of Farewells."