I am meeting friends in May. As we have an open itenenary how do I get tickets to see the Sagrada Famamilis? Friends said they had to buy 3 mos ahead and set a day and time before they left the US. Is there a way to buy a week before and skip the long lines? I do not want to miss it but not sure what days I will go to Barcelona. We now think we will be in that area end of May.