ATHENS, Greece (AP) — Millions of Orthodox Christians across eastern and southern Europe, the Middle East and elsewhere in the world have celebrated Easter. The most important holiday on the Orthodox religious calendar is essentially an outdoor celebration, with equally intense spiritual and pagan parts and religious services followed by feasts, familial and communal. Some customs may predate Christianity, but new ones, or variations of the old, constantly evolve. In an Athens neighborhood, younger parishioners have added petrol bombs to the customary launching of flares as soon as the priest intones "Christ has risen" at midnight on Saturday. Easter is also the occasion of a mass exodus from big cities to the countryside.