Each side-chapel comprises a large mosaic with a central image depicting the theme of that Mystery, and an inscription in Latin.

For example, the side chapel directly behind the altar contains a depiction of the Crowning with Thorns, which is surmounted by an image of the Ark of the Covenant (see figure).

[2] This depiction, of a very young woman facing directly forwards, is much more in keeping with Bernadette's descriptions of the apparition than the iconic statue in the niche in the Grotto.

In 1941, the white marble side doors of the basilica were engraved with a message of gratitude to Marshal Philippe Pétain, who visited Lourdes in 1941 and allowed the Church to reclaim ownership of the Domain.

In translation, this inscription read: In memoriam 1940-41, on the morrow of our disasters, France is trying to rediscover her soul under the government of Maréchal Pétain.