At the age of 36, Justo contracted Tubercolosis. The monastic life became more complicated, so fort the safety of the Monastery, he decided to leave. At the same time he inherited a plot of land in Mejorada del Campo. He promised himself that if he survived the illness he would build a cathedral in honour to the Virgin Mary.

Justo then started building the cathedral with no definite or written plans. He was inspired mainly by Romanic style architecture, which according to him is the finest architectural style. Other sources name as other influences Spanish Fortifications, St. Peter’s Cathedral in Rome and neo-classical architecture

A few years later, the building starts taking shape. Justo works mostly on his own, using recycled materials and developing impressive unique building techniques. Sporadically he gets help from his family or gets some paid help when he can afford it.

Around the year 1998, Angel, his main assistant, join the works. The operation get a massive boost. Angel works on the windows, decoration and floors, while Justo keep working on the towers and Dome.

In 2005 the Cathedral starts getting worldwide attention. Justo is contacted by Aquarius, a Spanish soft drink company, to take part in their advertising campaign which would feature his story. In change, he will get more funds to help the building of his Cathedral. The campaign is really popular in Spain, even tho a lot of people think its a publicity stunt. Slowly people starts realising that this is a real story and starts visiting Mejorada del Campo to see this incredible work.

In recent times the Cathedral was threatened of demolition in several occasions, furthermore, the Catholic Church refuses to adquire the Cathedral, as its deemed dangerous, even tho not even a stone ever fell from the roof, according to Justo.

In 2018 a young creative startup based in Liverpool UK, Scan And Make, got in contact with Angél to ask the availability of spaces in the cathedral to organise their exhibition of technology and art,  Making Art 4.0. After the exhibition, the startup offered their technological skills to help Justo and Angel collecting funds to make the cathedral safe and complete it.

In february 2019, the famous british TV Architect George Clarke, features a special on the cathedral on his show "Amazing Spaces" on Channel 4. Justo's story features on prime time television in the UK.

At the end of this year, the 4th edition of the Making Art 4.0 will take place in the Cathedral bringing more interest and visitors.