Pope Francis is warning Cubans about the dangers of ideology when others are excluded.  Celebrating Mass Sunday in Havana's Revolution Square, the pontiff urged the tens of thousands in attendance to serve one another. 

He said during his homily, that "service is never ideological, for we do not serve ideas, we serve people."  Pope Francis later met with retired Cuban leader Fidel Castro in a meeting the Vatican said was "very relaxed" and "friendly."   The Vatican says Francis and the 89-year-old Castro exchanged books and some other gifts.  Castro's wife and other family members were also at the meeting. 

Later this week, the pope will make his way to the U.S. where he'll address a joint session of Congress, meet with President Obama, and celebrate Mass in Washington, DC, New York City, and Philadelphia. 

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