While American influenced cultures celebrate Halloween today, here in Catalunya it is the Castanyada, although to be fair Halloween is becoming more popular, probably because of the number of UK and American immigrants.
In Catalonia, celebrations involve eating castanyes (roasted chestnuts), panallets (special almond balls covered in pine nuts, bottom right in photo above), which i really don't like, and moniatos (sweet potato), which i love, indeed I may roast one for my supper this evening.
Around the time of this celebration, a couple of huts are put up here in Vilanova, one in the Rambla, and one near the station, selling roasted chestnuts. The smell as you pass by is delicious, and many a times I've had to stop and buy some.
It seems that the tradition of eating these foods comes from the fact that during All Saints night, campanologists (bell ringers) would ring bells in commemoration of the dead into the early morning. (Unlikely to happen this year with the 10 - 6 curfew) Friends and relatives would help with this task, and everyone would eat these foods for sustenance.
Other versions of the story state that the Castanyada originates at the end of the 18th century and comes from the old funeral meals, where other foods, such as veggies and dried fruit were not served. The meal had the symbolic significance of a communion with the souls of the departed: while the chestnuts were roasting, prayers would be said for those who had died.
The festival is usually depicted with the figure of a castanyera: an old lady, dressed in peasant's clothing and wearing a headscarf, sitting behind a table, roasting chestnuts for street sale. Children (And some adults) now dress up in similar fancy dress.