The Safety of Europe
Byzantine Walls saved Europe for hundreds of years, being in between the European nations of the West and the invading nations of the East.
After continuous attacks (even western attacks!), the Byzantine Walls fell at a time when western Europe was strong enough to defend itself against Islamic Jihad.
Beyond the military aspect, Byzantine Walls saved Europe by just being a territory of culture, an exemplar to the barbaric at that time nations of the West.
Byzantine culture, alive today even without the Byzantine empire, continues to safeguard the future of Europe – if Europe decides to have a future. It is this culture that is able to give to the life of modern European nations a real and complete meaning.