With sunlight bathing silvery olive groves and patchwork vineyards, few places on the globe are as romantic and relaxing as Tuscany. And this intimate atmosphere is what prevails at Borgo Petrognano, an elegant estate hidden in the heart of Tuscany less than an hour from Florence, Siena and Pisa. Dominating this luxury retreat is a medieval tower, undoubtedly a reminder of the ancient city of Semifonte destroyed in 1202 A. D. by Florence, its rival