Ulldecona Main Festival Activity · Ulldecona, Montsià, Tarragona Image of Ulldecona, not of the place itself. Ulldecona's Festa Major is held beside the Gothic church of Sant Lluc, begun in 1373, in a town where in 1836, during the First Carlist War, Ramon Cabrera's bands defeated the Liberal forces. Photo: DagafeSQV (CC BY-SA 3.0) What to see and do in Ulldecona