I went to Barcelona by chance.

My brother's wife and daughters had been delighted by this elegant city in northern Spain and especially by the basilica of the Holy Family.

They convinced my brother that he too needed to see the city and he asked me to join him on a visit.

Naturally I knew of the church and of Pope Benedict's enthusiasm for it. One of the architects of the new Benedict XVI Retreat Centre of Sydney archdiocese had also written an article of commendation.

While I shared many of their artistic judgments, I was put off by photos of the basilica's exterior. It all seemed a bit loopy: Picasso in Hollywood.

But I knew nothing of the basilica's interior (and not much more, in fact, about the exterior). I was quite prepared to be unimpressed.

My visit completely changed my opinion as the basilica is a work of genius. This place of worship speaks of God to the people of today (and tomorrow) more eloquently then any church I know.

Catholic symbols are everywhere, teaching about Christ, the Church, light and life. Already 3,200,000 paying tourists visit each year, so enabling the construction to be continued.

The church is the product of Spain's turbulent religious history, and during its comparatively brief lifespan it has already been damaged and closed for a time by anti-Catholic violence.

In the 19th century, Barcelona was a centre for industrial development when Spain changed from being a colonial and largely rural society.

As the democratic, anti-religious and violent forces unleashed by the French Revolution of 1789 spread across Europe, the Spanish state, in 1836, expropriated all the Church's lands and assets.

In the consequent spiritual crisis the rise of militant unbelief was strongly contested by many Catholic priests and people.

The Association of the Devotees of St Joseph was founded in 1866 by the bookseller and philanthropist Josep Maria Bocabella, and grew strongly to a membership of half a million. In 1878 they decided to build an expiatory temple of prayer and worship dedicated to the Holy Family.

Work began in 1882, inspired in part by devotion to the Holy House of Nazareth, which was brought to Loreto, in Italy, in the 13th century, probably by Crusaders. Continue reading

• Cardinal George Pell in Catholic Herald

Work commenced on Sagrada Familia in 1882. A year later the project was taken over by Catalan architect Antoni Gaudi, who transformed the project with his particular style. Dedicating the last years of his life to the project, Gaudi died in 1926.

Gaudi is affectionately known as "God's architect" and the Vatican is considering a petition by the Archbishop of Barcelona to beatify him. When he died after being run over by a tram only a quarter of the project had been completed.

When it is finished the basilica will have three façades: the Nativity, the Crucifixion and the Resurrection.

Work on the last phase has yet to start.

In 2010 construction passed its mid-point, and Sagrada Familia was consecrated by Pope Benedict, and proclaimed a 'minor basilica'.

The hope is that Sagrada Familia will be completed by 2026, the hundredth anniversary of Gaudi's death.

Sagrada Familia gets praise from art critic Rainer Zebst, who says it's "probably impossible to find a church building anything like it in the entire history of art", while architect Paul Goldberger called it "the most extraordinary personal interpretation of Gothic architecture since the Middle Ages".

Reflecting its special cultural and physical significance, the nativity façade is listed by UNESCO as a World Heritage Site.

A recent video provides a spiritual journey through Sagrada Familia, a journey yet to be completed.