A rare tour of Antoni Gaudí's unfinished masterpiece reveals little-known details tucked away among its famous façades, soaring columns and colourful stained-glass windows.
Among the highlights is a numbered grid on the Passion Façade often mistaken for a sudoku puzzle. According to the basilica's rector, Monsignor Josep Maria Turull, it is actually a "magic square" in which every row, column and diagonal adds up to 33, the age of Jesus at the time of his crucifixion according to Christian tradition.
