I had been researching online tickets for Sagrada Familia in Barcelona and saw a lot of availability for various types of tickets and tours (audioguide, guided tour, towers, etc.) but when I was ready to purchase them, I went to the site recommended in RS Spain guide - www.sagradafamilia.cat, only to find much more limited availability. Shocked and disheartened, I decided to search "official Sagrada Familia website" and found the one I had looked at originally - https://sagradafamilia.org/en/. I was relieved to see that the range of availability was still there and the prices were lower on this site, too. I was able to purchase tickets for an audio tour and visit to the Nativity Tower for my husband and the audio tour for me, and was able to get them for an even cheaper senior rate. We can both be admitted when it opens at 9:00 am so we hope to beat at least a little of the crowd.
Just thought I'd pass this on.