In his remarks to the 600,000-strong crowd, the pope issued his strongest denunciation of religious intolerance yet in Cuba.
He referred to the biblical account of how people persecuted by the Babylonian king "preferred to face death by fire rather than betray their conscience and their faith."
He said people find freedom when they seek the truth that Christianity offers.
More top news
A suspected drunk driver ploughed into a crowd during Mardi Gras celebrations in the southern US city.
The singer had been tweeting in support of migrants when she was bombarded with abusive messages.
Ministers are reportedly considering plans in a bid to lower inward migration.