Colours are good but it's a little overexposed. If you use levels to make it less bright, the tower will stand out much better. Compositionally it's good and it's a nice picture, it's just a bit lacking in interest, it's a shame there aren't arrow slits or something on the tower.
The vapour trails spoil it as well a little, they didn't have midieval jet planes.
The gate also spoils it, maybe if you took a shot with the camera horizontal and having the bottom of the frame starting above the gate, the wider perspective would bring out more interest.