This route is located in the Sierra de Noez, just half an hour by car from Finca Los Pájaros Rural House. It receives this name because of Los Castillejos, which is nothing other than the remains of some trenches preserved from the Civil War.
It is a circular route of ten kilometers, with a medium-high difficulty, which takes approximately three hours.
The advantage is that you can get to know the whole of this mountain range with wonderful panoramic views as the horizon is clear in all directions.
More information here