I thought I will post pictures of this very prominently visited Basilica of Barcelona. It is one of the highly recommended places to visit, if you happen to be in Barcelona. And trust me, it is worth every second of your visit. You can get a lot of information about this from their website anyways. But it was a sheer pleasure to be there with all those lights and different architecture surrounding you. It is supposed to be completed (the construction i.e.) only in 2026. So yes, you will still see a lot of construction going on. They also have a workshop inside in a different area where they create the miniatures of what they are building and it’s truly amazing. Not to mention a school to explain you in detail of what they are doing.
With respect to the Magic square that is seen on the outer facade of Church, this is what they explain.
The Passion façade of the Sagrada Família church in Barcelona, conceptualized by Antoni Gaudí and designed by sculptor Josep Subirachs, features a 4×4 magic square:
The magic constant of the square is 33, the age of Jesus at the time of the Passion. Structurally, it is very similar to the Melancholia magic square, but it has had the numbers in four of the cells reduced by 1.