In the coming days Spanish Constitution Day on Tuesday, 6th December, will merge with the Catholic Feast of the Immaculate Conception on Thursday 8th, to create one very long winter public holiday.
So expect Andorra (Pyrenees)’s biggest annual traffic jams to start on Saturday as cars come in from Spain (Catalonia) and to last all week as people come and go taking long weekends at one end of the week or the other or taking the whole week off, with a final surge going back into Spain on Sunday, 11th December, starting before midday and lasting well into the evening.
(Puríssima has been celebrated in Spain since the 14th century, presumably without traffic jams).
See also Andorra travel guide
See also Pyrenees travel guide
See also France travel guide
See also Spain travel guide
