Simancas

Simancas is a handsome hilltop town above the Rio Pisuerga, about 6 km from Puente Duero. You'll cross a medieval bridge to reach it, then face a short but sharp climb to the Plaza Mayor, where a large Romanesque church and a rebuilt castle await.

The castle — Archivo General de Simancas — is one of Spain's most important historical archives, housing documents dating back to the Catholic Monarchs. You can't browse the stacks, but the building itself is impressive.

There are bars and services in town, though not everything may be open early in the morning.