Catholicism is the largest denomination within Christianity. Christianity itself is the largest religion in the entire world, hence Catholicism is a major world religion.
Catholicism.
Catholicism is the major religion of Turin, Italy.
A major religion practiced in Andorra is Roman Catholicism.
Catholicism
Catholicism
If it is Lyon in France, then Catholicism.
Catholicism
According to Operation World, the major religion in Congo is Christianity, primarily Catholicism.
The main religion in the Dominican Republic is Roman Catholicism.
Roman Catholicism
Roman Catholicism
Islam is the second major religion, although far behind the leading religion, Christianity (mainly Catholicism).