Pope Francis will make his first international visit since his visits Brazil - the worlds largest Catholic country. His six-day trip includes mass on Copacabana beach and a visit to the favela shanty towns.
Security concerns have been raised as he has chosen to walk around the favelas rather than travel in the bullet-proof Pope mobile.
Pope Francis drew an estimated three million faithful to Copacabana Beach to give one of the most important speeches of his pontificate.
One of Catholicism's oldest traditions can now be gained through social media including Twitter and Pinterest says a leading Cardinal.