St Joseph's Catholic Primary School in Bulli unveiled the finished Cosmic Walk mosaic on Thursday, April 11, the culmination of a project that began back in 2021.

The mosaic contains almost 26,000 tiles and acts as a timeline, depicting first the Big Bang 13.7 billion years ago and progressing through the formation of galaxies and the solar system through to the emergence of life and the present day.

It ends with a book and a flame, from the school's crest, which Catholic Education Diocese of Wollongong (CEDoW) professional officer Beth Riolo said aimed to encourage students to make their own positive contributions to this ongoing story.

"The idea is that the students have this... tangible reminder of their place in the universe, that they're part of this unfolding story that's been a long, long time in the making," Ms Riolo said.

She said the mosaic aimed to connect the scientific knowledge of how the universe came into existence with a Catholic faith perspective, while also representing the Dreamtime stories of the Dharawal people.

Ms Riolo described the mosaic as an artwork that was probably unique to not only Australia, but the world.

The mosaic was designed by art teacher Paola Birac and CEDoW staff member John Charadia, who works in gifted education.

They led the creation of the piece, overseeing the mostly students - but also parents, teachers and other staff members - who laid the tiles.

"It was a real community effort," Ms Riolo said.