Mistra (Mystras), Sparti, Peloponnese
The archaeological site of Mystras is vast and one should devote at least several hours (better: a full day) to exploring it.
Getting there involves a steep climb but the effort is rewarded by many beautiful views and, of course, the wonderful byzantinic architecture including a castle, several important churches, palaces, convents a museum and some normal houses.
I especially enjoyed the scenic layout and the many overgrown paths, old stairs and dorrways.
Like with many transcribed places names, quite a confusion exists concerning the spelling of the Greek place name Μύστρας in our alphabet: Mystras, Mystra, Mistra, Mistras.