Transcript for Inside the Historic Double Canonization
Bells of saint -- it just -- the workers are setting the scene for the canonization two popes to -- up at that altar is where it will take place. And up those steps. We'll come the relics the flash of John the 23 the blood of John Paul the second. While cardinals bishops. And up to a million pilgrims witness the event there are big screen TV set up around roam around the world. This is a moment of profound holiness and profound unity for all of the Catholic Church it's a day to remember for Catholics around the world. Two popes being canonized not just any two posts at the same time but to really. Transformational. Estimated rate difference in the life -- the church in the last century probably the two popes who. Change the church the most and many people have had the privilege really of knowing both John Paul. The second ends on the 23. In witness that the lives of two saints in the modern -- it's it's not a question of -- saint. From some you know distance century we have no idea about the personality how they actually were. These are lives that are recorded we've watched them. And now they're saying it's. Terry Moran ABC news Vatican City.
This transcript has been automatically generated and may not be 100% accurate.