Please follow the museum itinerary. A few meters from the ticket office you will find the toilets. As you stay on the museum itinerary, you will make a short walk up the stairs in the direction of the sign “Il Passetto”. Keep going until you reach the Bastions Level (level 2 of the Castel). When you spot a canon at your right (having Saint Peter’s Basilica in the far background), keep walking until you arrive at the Bastion of Saint-Marc (Bastione San Marco). The Bastion is part of the Castel and leads to the Passetto (number 3).