* Outspoken defender of poor visits home in Rio favela
* Challenges politicians to narrow gap between rich and poor
* Huge crowd as pope opens Catholic world youth jamboree (Recasts with huge crowd on beach for opening of jamboree)
By Philip Pullella and Anthony Boadle
RIO DE JANEIRO, July 25 (Reuters) - Pope Francis on Thursdayissued his first social manifesto, calling on the rich to wipeout vast inequalities, and later received an ecstatic welcomefrom up to a million people on Rio's famed Copacabana beach.
During a visit to a Rio slum on Thursday morning, the firstLatin American pope called for a "culture of solidarity" toreplace the "selfishness and individualism" in modern society.
"No one can remain insensitive to the inequalities thatpersist in the world," he told residents of Manguinhos, asprawling shantytown, or favela, of ramshackle brick dwellingsthat until recently was overrun by violence and controlled bydrug lords.
His speech, under rains that have persisted throughout mostof his first trip abroad as pope, came halfway through aweek-long visit around World Youth Day, an internationalgathering of young Catholics.
Despite the downpours and unusually chilly weather, tens ofthousands of jubilant Brazilians and foreign visitors haveturned out to welcome the pope. Vatican radio estimated thecrowd at Copacabana at up to 1 million.
The World Youth Day events are an effort by the Vatican toinspire Catholics at a time when rival denominations, secularismand sexual and financial scandals continue to lead some toabandon the Church.
Brazil, home to the world's biggest population of Catholicswith over 120 million faithful, is an apt locale for the pope toremind the world of inequality. A recent decade of economicgrowth in the country raised incomes for many, but tens ofmillions of Brazilians still live in poverty or with little morethan the basics to get by.
In Manguinhos, Francis, an Argentine known for frequentoutings into the slums near Buenos Aires even as a cardinal,smiled and visibly enjoyed the chaotic close contact withresidents there. He called for more efforts to end poverty andsaid authorities must do more than just crack down on the drugtrade to ensure opportunities for those at the bottom of theeconomic ladder.
"Everybody, according to his or her particular opportunitiesand responsibilities, should be able to make a personalcontribution to putting an end to so many social injustices," hesaid in an address on a muddy, rain-drenched soccer field nextto a river smelling of sewage.
Making the speech after blessing the favela's small chapeland visiting one of its homes on a recently cleaned street, thepope challenged the rich and powerful to use their influence toenact lasting change.
"I would like to make an appeal to those in possession ofgreater resources, to public authorities and to all people ofgood will who are working for social justice: Never tire ofworking for a more just world, marked by greater solidarity!" hesaid.
On Thursday night, when Francis presided at the World YouthDay opening on Copacabana beach, he was driven slowly through ahuge adoring crowd, stopping to kiss babies and even to give hiswhite skullcap to someone who had sewn a home-made one for himand ran to the car to hand it to him.
The weather, which has been wreaking havoc on events, forcedorganizers to move this weekend's two final gatherings toCopacabana from a pasture on the outskirts of the city becauseit had become a vast field of mud. (Editing by Paulo Prada, Vicki Allen and Cynthia Osterman)