This tradition has two churches fighting a holy rocket war
The Greek town of Vrontados on the island of Chios has an Easter tradition they call Rouketopolemos, which literally means Rocket War.
This annual event pits two rival parishes against each other by firing tens of thousands of home-made rockets at the opposing side's bell tower. The next day, both congregations count the direct hits to determine the winner, but no matter the results, each parish claims victory. Since both sides end in disagreement, they agree to settle the score next year, thus perpetuating the rivalry.
The origins of this tradition are unclear, but one popular story states that it was born from the Turkish occupation of Greece. People from the island were prohibited from celebrating Easter the way they used to. So, the Christians from the churches of San Maria and San Marco decided to have a fake war with rockets to keep the Turkish away. Frightened by the sudden violence, the Turkish kept their distance. In the meantime, the communities celebrated Easter they way they were accustomed to, according to Rocketwar.
The midnight rocket war is truly a spectacle, the action begins at 3:40 of this video: