Paying homage to his native city in a lyrical and evocative style, Venice Is A Fish: A Sensual Guide by Tiziano Scarpa guides readers down tiny alleys, over bridges, and through squares, daring us to lose ourselves, forget the guidebooks, and experience Venice as Venetians do.

Venice Is A Fish provides no hotel ratings or museum hours. Instead, in a delightful initiation, Scarpa tells us how to balance while standing on a gondola; where lovers will find the best secret hiding places; the finer points of etiquette and navigation during a auga alta; and how to best defend ourselves from the pitiless beauty of one of the world's most stimulating cities. Open Venice Is A Fish, and Scarpa's magnificent images, secret history and hidden lore unfold like a treasure map of the senses.

On the map, the bridge connecting it to terra firma looks like a fishing-line: Venice looks as if it's swallowed the bait. It's doubly bound: a steel platform and a strip of tarmac; but that happened afterwards, just a century ago. We were worried that Venice might one day change its mind and go off travelling again; we fastened it to the lagoon so that it wouldn't suddenly get it into its head to weigh anchor and leave, this time forever. We tell everyone else we did it for its own protection, because after all those years in its moorings, it's lost the knack of swimming: it would be caught straight away, it would end up on some Japanese whaling ship, or on display in a Disneyland aquarium. The truth is that we can no longer do without it. We're jealous. And even sadistic and violent, when it comes to keeping someone we love. We've done something worse than tying it to terra firma: we've literally nailed it to the sea bed.

In a novel by Bohumil Hrabal there's a child who's obsessed with nails. He constantly hammers them into the floor: at home, in a hotel, when visiting other people's houses. All the parquet floors that come within his reach are hammered away at from dawn till dusk. As though the child wanted to fix the houses to the ground, as a way of feeling more secure. Venice is made just like that; except that the nails are made not of iron but of wood, and they're enormous, between two and ten metres in length, with a diameter of twenty or thirty centimetres. They're planted in the slime of the seabed.

These buildings that you see, the marble palazzi, the brick houses, couldn't have been built on water, they would have sunk into the mud. How do you lay solid foundations on slime? The Venetians thrust hundreds of thousands, millions of poles into the lagoon. Underneath the Basilica della Salute there are at least a hundred thousand; and also at the feet of the Rialto Bridge, to support the thrust of the stone arch. St Mark's Basilica rests on big oaken rafts, supported by elm-wood stilts. The trunks were floated down to the lagoon along the River Piave, from the Selva di Cadore on the slopes of the Venetian Alps. There are larches, elms, alders, pines and oaks. La Serenissima was very shrewd, she always kept a close eye on her wooden possessions; the forests were protected by laws of draconian severity.

Upside-down trees, hammered in with a kind of anvil hoisted on pulleys. I had the chance to see them as a child: I heard the songs of the pile-drivers, sung to the rhythm of the slow and powerful percussion of those cylindrical mallets suspended in the air, running on vertical rails, slowly rising and then crashing back down again. The trunks are mineralised precisely because of the mud, which has wrapped them in its protective sheath, preventing them from rotting in contact with oxygen: breathless for centuries, the wood has been turned almost to stone.

You're walking on a vast upside-down forest, strolling above an incredible inverted wood. It's like something dreamed up by a mediocre science-fiction writer, and yet it's true. Let me tell you what happens to your body in Venice, starting with your feet.

feet

Venice is a tortoise: its stone shell is made of grey trachite boulders (maségni in Venetian), which pave the streets. All the stone comes from elsewhere: as Paolo Barbaro has written, almost everything you see in Venice comes from somewhere else, it's been imported or traded, if not actually plundered. The surface you are treading on is smooth, although many of the stones have been beaten with a small milled hammer to keep you from slipping when it rains.

Where are you going? Throw away your map! Why do you so desperately need to know where you are right now? OK: in all cities, in the commercial centres, at bus stops or underground stations, you're used to having signs that hold you by the hand; there's almost always a big map with a coloured dot, an arrow to bellow at you, 'You are here'. In Venice, too, you need only look up to see lots of yellow signs with arrows telling you: you've got to go this way, don't get confused, To the Railway Station, To San Marco, To the Accademia. Forget it, just ignore them. Why fight the labyrinth? Follow it, for once. Don't worry, let the streets decide your journey for you, rather than the other way round. Learn to wander, to dawdle. Lose your bearings. Just drift.

Do what we call 'acting Venetian': after the war the phrase alluded to our football team, 'doing the Venetian', 'doing a Venice'. Our footballers had an exasperating, selfish style of play, always with the ball at their feet, loads of dribbling and hardly any passing, a limited vision of the game. Of course they did: they'd grown up in that varicose whirlpool of alleyways, little streets, sharp turns, bottlenecks. So obviously, even when they took to the field in shorts and jerseys, they went on seeing calli and campielli — streets and squares — everywhere, and struggled to disentangle themselves from a private labyrinthine hallucination between the midfield and the penalty area.

Imagine you're a red blood cell running along some veins: you follow the heartbeat, you allow yourself to be pumped by that invisible heart. Or else you're a mouthful of food being carried along by the intestine: the oesophagus of an extremely narrow calle squeezes you between brick walls until they are practically grinding you, then pushes you out, sends you slipping through the valve of a bridge that flows to the other side of the water and deposits you in a wide stomach, a campo from which you can't continue without first having paused for a while, forced to stop because the façade of a church holds you back, chemically transforms you to your very depths, digests you.

The first and only itinerary I suggest to you has a name. It's called: at random. Subtitle: aimlessly. Venice is small, you can afford to get lost without ever really leaving it. At the very worst, you'll always end up at the water's edge, looking out over the lagoon. There is no Minotaur in this labyrinth, no aquatic monster waiting to devour its victims. An American friend of mine came to Venice for the...