>>17907988 (OP)
I like the reconstructions of european castles. Many were simply abandoned, destroyed or were transformed with the times that they nowadays are palaces - but with some educated guesses one can recreate the various possible stages of their existance.
Due to my university studies in Geography I quite like reconstructions that are based on the early earthen fortifications of Europe during the early middle ages.
Pic rel is the Haldenburg - a fort dedicated to the defense against magyar raiders. Caracteristic of such fortifications are the obstacles in front of the palisades: ditches vertical to the wall, stakes, throny brushes and abatis. All dedicated to the task of negating the approach of cavalry and forcing an infantry engagement.