Barcelona in January is not really about the night-time Gothic Quarter which, admittedly, does look sinister in the winter. It's not about the Park Guell which is worth your while in any season. It's not even about the gust of warm air that cures your choked lungs the second you leave the airport. Barcelona in January is all about those trees whose crooked branches look like the fingers of a witch ripping her hands through the ground. It's a city of sinners, no doubt.