Perched above the Rio Lozoya in the province of Madrid lies the picturesque walled town of Buitrago del Lozoya.  It was founded by the Romans and fortified by the Moors. In later centuries it became an important medieval market town. The 14th century castle built by the Mudejars is now a ruin although stretches of the original wall are still intact.  Inside the protective walls lies the town, with its 15th century church of Santa Maria del Castillo.  There is also a Picasso Museum displaying some original work which was donated by Picasso's friend Euginio Arias who worked as a barber in the village.