Are you interested in history you may follow the route called Ruta del Conde Fernán González through:
The ruins of the monastery San Pedro de Arlanza: where the Count Fernán González and his wife Sancha were buried.
The ermitage chapel at Quintanilla de las Viņas: the remains of a visigothic church from late seventh century.
The monastery at Santo Domingo de Silos: Visit the romanesque cloister, the museum, the pharmacy whith more than a thousand pots made of ceramics from Talavera and its laboratory. When paying a visit to the monastery, it is a good hint to do so half an hour before closing time, then you will avoid the worst rush hours. www.silos.arrakis.es
La Yecla: A 300 meters path takes you through a narrow mountain pass. Fascinating nature and views.
Lerma: Guided tours start from the Tourist Office and take you through the most important sights such as the Saint Peters church and several monasteries.  www.citlerma.com/

The area of Ribera del Duero.
The ruins of the roman city of Clunia has some interesting mosaics that can be seen only during summer. Peñaranda de Duero has a medieval castle, a renaissance palace and a collegiate church.
We are only some 40 Km. from Burgos, capital of the province, so do pay a visit to the magnificent gothic cathedral, the medieval monastery of las Huelgas, La Cartuja de Miraflores, or see the sights onboard a tourist train that takes you through the city.
For further information, visit some of the principal web pages of Burgos and the province, with visiting hours, agenda and other interesting things:

www.patroturisbur.es          vwww.diputaciondeburgos.es          www.turismocastillayleon.com
50 Km to the north you will find The archaeological site of Atapuerca. Of capital importance in European prehistory.

www.atapuerca.net
Valley Ura

 La Yecla
: straigh way between mountains