Modern day Salamanca still boasts many of the historical buildings from this time, and the Old City is a UNESCO World Heritage Site. Amongst the most impressive structures are several of the original university buildings, as well as many churches and convents of differing architectural styles.
The are around Salamanca is not the best for cycling in Spain; however, there are a couple of options if you wish to include this on your holiday. The first thing to note is that average high temperatures in July and August are 30 degrees celsius; unless you have a lot of experience in this kind of heat, we would recommend spring and autumn as better times of the year to visit.
One popular cycling route that passes through the city is the Via de la Plata (Way of Silver) - a Roman route from Sevilla to the north of the country. It is also one of the many routes of the Camino de Santiago; however, at nearly 900km, the whole route is only recommended if you are going on a longer holiday. The route follows the N-630 road both north and south of the country; despite being a national road, there is relatively little traffic as a motorway runs parallel to it. The scenery here is typical of the region: largely arable farmland and it is only very gently undulating in places.
Another option is to base yourself close to one of the natural parks which are around 100km from Salamanca. From here you can take a couple of days out to ride there and back to Salamanca, whilst also benefiting from the more interesting countryside elsewhere. To the west is the Arribes del Duero on the border with Portugal - this is a picturesque park with several rolling routes. To the south, the Sierra de Gredos and the Batuecas-Sierra de Francia offer more mountainous routes - with some climbs over 1000m in altitude, but with gradual gradients. The latter of the two is the best choice, with some fine scenery and several different roads, all with little traffic.
Salamanca is certainly worth visiting for a day or two if you are on a long cycling holiday, but do not base yourself here for the whole trip, as there are not enough routes, or enough intersting scenery to make it worthwhile.
The areas to the south and east of Leon - towards Valladolid and Burgos are relatively flat. The scenery is not the most interesting - arable farmland for as far as the eye can see - but the road surfaces are good and, if you avoid the national (N-xxx) roads, there is not a great deal of traffic. We would only really recommending going this way, however, if you are touring the historic cities in the region (Burgos, Zamora, Valladolid, Palencia). If you are looking for a flat route, then there are flat parts of Andalucia, Valencia and Mallorca that offer much more interesting scenery. If, however, your main priority is discovering superb scenery by bike, then the areas to the north and the west of Leon are definitely worth a visit.