The Santa Barbara castle can be seen from the road by Villa de Teguise, at the border of the Guanapay volcano. It is definitely worth a stop as you are driving through the Lanzarote island in the Canaries (Spain). It is the oldest preserved military construction on the island.
It is quite windy up there! but the views are stunning!
See for yourself, my pictures of the Santa Barbara castle taken in a month of December: