On the northeast flank of the Serra da Estrela, the tallest mountain in the country, Guarda is Portugal's highest city, at 1056 meters (3320 feet); it was founded in 1197 to act mainly as a frontier guard (thus its name) and its appearance is rather austere.
From Guarda you can drive to Manteigas, right in the heart of the Serra da Estrela, whose highest point rises to 1993 meters (6643 feet).
This is also the district to take the border castles tour: in its early history, Portugal had a vital need to defend itself from Spanish attacks.
Thus, several castles were built along the border from as early as the 13th century, but many were later rebuilt after being partially destroyed by sieges (Spanish and French); Figueira de Castelo Rodrigo, Pinhel and Almeida are good examples of this part of Portugal's history.
Another imposing and well preserved castle lies in Sabugal, while in Sortelha the 13th century castle, stony lanes and granite houses are enchanting.
In Trancoso, the old Judiaria (jewish quarter), with its quaint houses, reminds us of the large jewish population that lived there in medieval times.
But in this district you can go way back from medieval times: in the environs of Vila Nova de Foz Côa, you can see the world's largest collection of open air Stone Age engravings, in the Archaeological Park of the Côa Valley.
The engravings, which depict horses, bulls, fish and a naked man, are estimated to be more than twenty-five thousand years old, and UNESCO has declared the Park a World Heritage site.