The Danube narrows sixty kilometres north of Budapest and turns sharply westward, carving a twenty-kilometre arc through the Visegrád Hills that Hungarians call the Duna-kanyar — the bend that held the kingdom's northern frontier for a thousand years. Three towns anchor the loop: Esztergom, where Saint Stephen was crowned in the year 1000 and where the largest basilica in Hungary now rises above the Slovak border; Visegrád, whose thirteenth-century citadel commanded the river from a three-hundred-metre limestone spur; and Szentendre, a Serbian settlement rebuilt by Orthodox refugees in the seventeenth century whose cobbled lanes and baroque spires remain intact. The bend became a royal corridor in the Middle Ages. King Matthias Corvinus built a Renaissance palace at Visegrád in the 1470s, importing Florentine architects and filling the terraces with red-marble fountains that were excavated only in the twentieth century. Esztergom served as Hungary's ecclesiastical capital from the eleventh century until the Ottoman conquest in 1543, when the Turks fortified the basilica hill and held it for a hundred and forty-three years. The current neoclassical basilica, consecrated in 1856, contains the Bakócz Chapel — a Tuscan Renaissance gem completed in 1506, dismantled stone by stone during construction, and reassembled inside the new nave. Its Carrara marble altarpiece is the oldest intact Renaissance structure in Hungary. Szentendre retains the texture of an eighteenth-century merchant town. Serbian families fleeing Ottoman expansion brought icon painters, goldsmiths, and winemakers; seven Orthodox churches were built between 1690 and 1763, each topped with a slender tower rather than a dome to blend with Catholic neighbours. The town's position at the mouth of the Pilis range made it a Habsburg customs post, and wealth arrived in the form of silk, tobacco, and Tokaji wine. By 1770 Szentendre held five thousand residents and printed books in Cyrillic and Greek. The twentieth century emptied it — industry moved to Budapest, the Serbian population dwindled — but the Hungarian Open Air Museum opened on the northern edge in 1967, preserving two hundred vernacular buildings from vanished villages across the Carpathian Basin. The permanent collection includes timber churches from Transylvania, thatched farmsteads from the Great Plain, and a working windmill from 1838.