It was started 135 years ago, and it will be another nine before it is finally completed in 2026.

The Basilica of La Sagrada Familia (‘Holy Family’) was begun in Barcelona in March of 1882 and by the time it is finished it will have taken longer to build than all of Egypt’s pyramids, and just 50 years less than the 8,852km Great Wall of China.

And will justify what its pious architect, Antonio Gaudi, said when asked why it was taking so long to complete.

He replied simply: “My client is not in a hurry.”  His ‘client,’  of course, being God.

Gaudi died at 74 years of age when hit by a tram in 1926, his Sagrada Familia far from completed.

Many critics say builders have strayed widely from his original masterful concept, but as most of his plans were destroyed during the 1930s Spanish Civil War, today’s work relies largely on guesswork as to what Gaudi had in mind.

The huge centre-piece of the church will be eighteen massive spires: one for each evangelist, one for every apostle, and one each for The Virgin Mary and Jesus, His being the highest and central spire and 170m tall.

That final and tallest of these eighteen spires will make it the highest religious building in Europe.

The building is unique in European church architecture, combining as it does Gothic and Art Nouveau sensibilities into something that is at once whimsical and magnificent.

One of the reasons the Sagrada Familia's construction progressed so slowly was that it relied entirely on private donations. It was then interrupted by the Spanish Civil War, only to resume intermittent progress in the 1950s.

And, despite its size and grandeur, it cannot be called a cathedral, as that indicates the seat of a bishop, which it is not.

Today 3,000,000 people a year visit Sagrada Familia as work goes on around them, contributing E25million in entrance fees towards its completion in 2026 – the centenary of architect Gaudi’s death.