Castrotorafe is the ruined shell of a medieval fortified town on the River Esla, often described locally as "old Zamora." The surviving walls and castle fragments are open to the sky, with the river valley doing much of the work: this is a place for walking the earthworks and reading the landscape rather than touring restored rooms.
It is best as a half-day detour for travelers with a car or a specific interest in Zamora's frontier history. The site is quiet, exposed, and largely unrestored, so it rewards good light, sturdy shoes, and realistic expectations more than a checklist approach.