Please answer a question about the following article about Carnival:

In Catalonia people dress in masks and costume (often in themed groups) and organize a week-long series of parties, pranks, outlandish activities such as bed races, street dramas satirizing public figures and raucous processions to welcome the arrival of Sa Majestat el Rei Carnestoltes (His Majesty King Carnival), known by various titles, including el Rei dels poca-soltes (King of the Crackpots), Princep etern de Cornudella (Eternal Prince of Cuckoldry), Duc de ximples i corrumputs (Duke of Fools and the Corrupt), Marquès de la bona mamella (Marquis of the lovely breast), Comte de tots els barruts (Count of the Insolent), Baró de les Calaverades (Baron of Nocturnal Debaucheries), and Senyor de l'alt Plàtan florit, dels barraquers i gamberrades i artista d'honor dalt del llit (Lord of the Tall Banana in Bloom, of the Voyeurs and Punks and the Artist of Honor upon the Bed).

Where do people dress in masks and costume?
Catalonia