Russian language/bumper sticker question

Y MHE NET any good memory of how to construct nuances like this. I recognize it as the preposition o plus the instrumental case of Beslan. Wouldja be willing to explain the difference in connotation between the “Beslan” and the “o Beslane” constructions? (And thanks for the correction on the verb – I perpetually forget the significance of the perfective aspect, treating it like Western perfect cases.)