The Gironde estuary is wide enough here to feel like an inland sea, and Vauban saw it as the gateway to Bordeaux that needed a lock. His answer, at the end of the seventeenth century, was a triangle of fortifications: the citadel at Blaye on the right bank, Fort Médoc on the left bank at Cussac, and between them Fort Paté, a squat stone tower built on an island in the middle of the river. Together they could cross their fire over the shipping channel, and today they share a place on the UNESCO list of Vauban's works. The citadel of Blaye is the most impressive of the three, a fortified town in its own right, with ramparts, gates and old barracks set high on a bluff above the water.
Walking the walls is free, and the views across the estuary are wide and atmospheric, especially in the evening light, when the water turns silver and the Médoc shore becomes a low line on the horizon. Blaye's history goes further back than Vauban. The troubadour Jaufré Rudel was a lord of Blaye in the twelfth century, famous for his songs of distant love, and medieval legend held that Roland, the hero of the Chanson de Roland, was buried here. Later, the Duchess of Berry was held prisoner in the citadel in the 1830s after a failed royalist uprising.
The riding around Blaye is gentle and pleasant rather than dramatic. The Côtes de Blaye vineyards roll over low hills, with quiet country roads linking villages, chateaux and churches. The estuary road towards Bourg is a nice ride, with the river on one side and limestone cliffs on the other, some of them pocked with cave dwellings. Wind can be a factor, coming in off the Atlantic and funnelling up the estuary.
A small car ferry crosses the estuary from Blaye to Lamarque, a short crossing that drops you in the heart of the Médoc wine country near Fort Médoc and the great chateaux of Margaux and Pauillac. Blaye has fuel, shops and restaurants, and the town's market and its cafes make a good lunch stop. Try the local wines, of course, and if you see lamprey on a menu, that is the estuary speciality, cooked slowly in red wine.