Start from Acqui Terme, famous as a spa town since antiquity. Once you leave the railway station, go left along Via Alessandria, turn left again on Via Chiabrera, then carry on along Via Romita and turn right on Via Alfieri. When you reach the junction with Corso Bagni, turn left onto it, proceeding to leave the town centre and cross the bridge over the Bormida. Once you've crossed the bridge, go down on your right to the cycle path, which crosses the floodplain of the river and goes past the ruins of the ancient Roman aqueduct. The cycle path then runs alongside the SP 334. Enter this on the right as soon as it becomes possible. Once you reach the village of Melazzo, drop down into the Erro valley, take the SP 225 over the river and head up to Castelletto d’Erro. Carry on to Montechiaro d’Acqui, where you leave the SP 225 and head left on the SP 220, which takes you to Pareto. Shortly after the village, head back towards Acqui along the SP 217, passing first through Roboaro and then Malvicino. From the second village, go down to the bottom of the Erro valley, turn left onto the SP 334, go through Cartosio and back to Melazzo. From Melazzo, come back into Acqui along the same route you took to leave it. Alternatively, if you want to avoid having to turn left onto the cycle path, just take the SP 334. When you reach Aqui, before you go back to the station, it's worth a visit to the town centre to see the famous fountain with its hot, sulphurous water.