The correct spelling of the popular Spanish city is "Barcelona" (/bɑːrsəˈloʊnə/), not "Barcelonia". The phonetic transcription clearly indicates the stress on the second syllable and the "c" is followed by an "e" which makes the sound "s". It is common for non-Spanish speakers to make this mistake as they may assume that there is an "i" after the "c". Remember, always double-check the spelling of a word before using it to avoid any misunderstandings.