Before the Great Siege of 1565, the Sceberras Peninsula was uninhabited and unfortified, except for Fort St Elmo at its furthest point. Fearing another attack by the Turks, Grand Master Jean Parisot de la Valette (of the Knights of St John) began the task of building a new city on what was then just a barren limestone ridge. Valletta was the first planned city in Europe, with buildings tall enough to shade the streets from the hot sun, and straight streets to allow cooling sea breezes to circulate. A great ditch – 18m deep, 20m wide and nearly 1km long – was cut across the peninsula to protect the landward approach, and massive curtain walls were raised around the perimeter of the city. Spurred on by the fear of a Turkish assault, the Knights completed the fortifications in a mere five years.