US Catholic leaders and a select crowd of several hundred well-wishers were on hand to greet the pope, who wore his traditional papal whites and waved to the crowd, who chanted: "Ho ho, hey hey, welcome to the USA."
A small group of children from Catholic schools in the Washington area were brought forward to welcome the pontiff.
Obama will host the Jesuit pope at the White House on Wednesday.
In the United States he will find an American public that widely respects him, but has a less favourable view of the Catholic
Catholic (noun)
Meaning: Roman Catholic; a member of the part of the Christian Church that has the Pope as its leader
Thai Translation: สมาชิกของโบสถ์คาทอลิก
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Church.