In the Middle Ages, a large isolating wall was installed around the choir, forming a semi-chapel in the large cathedral, to encourage reflection. The canons, the cathedral’s priests, could go there to pray, set away from the noise that visiting pilgrims could make. This wall is home to sculptures that depict scenes from the life of Jesus, not unlike a magnificent comic strip.
On the North side, you can admire all the scenes from Jesus’ childhood, his baptism, and part of Holy Week. The wall that portrays the rest of Jesus’ life, in particular his death on the cross, is no longer in existence. The other choir wall, the South wall, shows scenes from His apparitions after the Resurrection.