The fast-track option was really very convenient and worth it, I highly recommend it. I would not recommend visiting such a landmark without a tour guide. Our tour guide was very knowledgeable and competent, we wouldn't know where to start and what to look at without his help. Besides that the whole tour went very smoothly and easily thanks to him having everything organized, otherwise it would have taken much more time with all entrances, long queues and security measures. I do recommend visiting the Sagrada Familia and then the towers at sunset, tour starting 4 or 5 pm, it is really beautiful and the view from the tower is breathtaking!

I would highly recommend booking through this company. I used them twice for my trip to Barcelona and on both occasions the guides were excellent. Our guide was George, he gave an extremely informative guide around the cathedral. Some very useful information which if you had gone alone would have surely missed.

Sagrada Familia is such an incredibly beautiful place and our tour guide, Juan, did a great job teaching us the history and explaining all of the intricate design elements. We went up in one of the towers at the end, which offered some great views of the city, but I wouldn't say it's a must do. Overall, a great experience!