Best time to do this is early morning - like starting at 7.00 am. You can start anywhere, of course, but we start with your back to the Bosco Verticale. Head up the slope edging the first park (BAM - Biblioteca degli Alberi di Milano) towards the UniCredit tower and Piazza Gae Aulenti (which you'll cross on the way back). At the top of the slope, head left past the IBM Studios pavilion and over the walkway just round to its right. Once you've crossed it, head straight on and down the steps that you won't see at first (you'll see some on the right but you don't want these). Down the steps, head straight on through the greenery and down to the road (Via Fabio Filzi). Go straight across at the pedestrian crossing and into a smallish road where you'll immediately pass the basement car park of the Hotel Principe di Savoia, Milan's swankiest. Immediately after the car park, go up the old steps to the right, run past the main entrance to the hotel and down to the very big and busy crossroads of Piazza della Repubblica. You need to get diagonally across this one way or another. Behind the buildings on the far side is the entrance you need to the second park (Giardini Pubblici Indro Montanelli, also referred to as the 'Giardini di Porta Venezia'). Go clockwise round the park. At the end of the first side, you'll come to the planetarium (Planetario), where you turn right. Just here, on this corner, there's one of Milan's 'vedovelle' ('little widows', on account of the tear-like flow of water) drinking fountains. You'll find a few along the route (there's another in the middle of Piazza della Scala and several in the parks - put your finger over the mouth of the dragon and the water comes out through the hole on its forehead). Continue from the planetarium past the big natural history museum on your right. After this, at the next corner, staying inside the park, turn right and head straight along this side until you come to the next corner where there's a statue of the interesting and controversial man himself (Indro Montanelli). Go out through the gate to your left and head for the arches at the start of Via Manzoni, which you have to go down. On your way along Via Manzoni, you'll go past the end of Via Montenapoleone (fashion and luxury shop mecca) on the left and, on the right, the historic Grand Hotel et de Milan, where Giuseppe Verdi stayed, composed and died. Towards the end of Via Manzoni, on the right, you'll get to La Scala opera house. Opposite it, on the other side of the square is the less famous Palazzo Marino, Milan's city hall. Cross the square (drinking fountain in the middle) and head straight into the Galleria Vittorio Emanuele. In the middle, if there's not a queue, you can spin on your heel on the bull's testicles (it's for good luck). Leaving the Galleria, you'll find yourself in Piazza Duomo but, before taking a step into the Piazza, go into the 'Camparino' bar on the right-hand corner of the Galleria. Do not sit down but go to the till, pay for a 'caffé', then go and ask for it, standing at the bar. Admire the mosaics. Exit the bar. Admire the Duomo. Head along the side of the Piazza where the bar is, go straight across the road at the opposite end to the Duomo into a pedestrianized area, where you'll see, on your left, another historic square and buildings (Piazza dei Mercanti). Keep heading straight on into Via Dante, which will take you, via Piazza Cordusio and Piazza Cairoli, to the castle (Castello Sforzesco). Go through its main gate and continue straight on until you get out of the other side. When you do, in the distance, you should be able to see the Arco della Pace arch on the other side of the park. That's where you need to go. This trail will take you over a pond on a nice little bridge ('Ponte delle Sirenette'), Italy's first ever iron bridge, originally crossing one of the canals, then transplanted into the park. To pass the Arco della Pace, you briefly exit the park, turning right, but then re-entering at the next gate and heading straight on, passing, on your left, the Arena Civica (built by order of Napoleon and used by Inter Milan before San Siro was built), then exiting through one of the many gates. If it's the one indicated on this trail, go left and it'll take you past the Acquario Civico. Admire the tiled facade with its fountain and, maybe some other time, visit it. Stay on the same side of the road and head left along the tree-lined pavement. On your left, inside the park, you'll see the Arena again. After this, you'll get to another complicated crossroads that you need to cross more or less diagonally, aiming to go behind and beyond the tall, modernish green-tiled block of flats into Via della Moscova. Do that and, after 100 yards, you'll get to another square with the Moscova underground station. Here, head leftish into Corso Garibaldi. Before you get to the end of it, turn right into a small, innocuous little street (Via Marsala). Go along this. Where it crosses Via Solferino, you'll see Cotti, a historic wine merchant (well worth a visit at some point). Straight on a few yards more and turn left into Via San Marco, running briefly beside the 'Conca dell'Incoronata', a still open but dry section of Milan's old canal system, complete with lock (Leonardo da Vinci had a hand in this) and lock-keepers booth. Immediately after this, don't go up the steps you see in front of you but through the pedestrian tunnel just to their left. Coming out into the small gardens the other side (another 'vedovella' here), diagonally get across the main road (Via Melchiorre Gioia) at the lights and take Viale Monte Grappa. The first main square along here contains an arch (Porta Garibaldi) and the Eataly good-food place. Here, turn right into Corso Como, at the end of which you should head up the slope that takes you back into Piazza Gae Aulenti. Admire it and then take a final trot round the park - to get you close to the 10 km mark - and back to Bosco Verticale. Then you could always go back up the slope into Piazza Gae Aulenti and have a nice cappuccino and warm croissant at the Illy bar.