Here's one of several hints that Andalucia is the Texas of Spain: not only did they build the biggest cathedral, but they make sure everyone knows it. This certificate is displayed prominently. Elsewhere, I've read that St Peter's in The Vatican and St Paul's in London have similar claims, but did they have the Guinness Book of Records verify it? We've also heard the claim qualified with "gothic cathedral" or "considering volume", so perhaps it's not that clear cut. Ha ha