Castile  and Leon is Spain's largest region bordering nine other regions and Portugal to the west.  The region is split into nine provinces,   Avila, Burgos, Leon, Palencia, Salamanca, Segovia, Soria, Valladolid and Zamora.  Each province has something of interest for the visitor.  From the beautiful university city of Salamanca to the cathedral city of  Burgos and the Roman aquaduct of Segovia, Castile and Leon is one of the best regions of Spain to explore the country's fascinating history.