BOGOTA/CARTAGENA, Colombia - Pope Francis wraps up his trip to Colombia on Sunday with a visit to the Caribbean port city of Cartagena, a top tourist destination famous for its colonial walled ramparts but which masks deep social inequality in its surrounding shantytowns.Cartagena's narrow cobbled streets and well-preserved church squares attract millions of visitors every year, the financial fruits of which barely touch the lives of the city's poor.The Argentine pope has so far during his trip focused his message on reconciliation and forgiveness for a 50-year civil war that has killed more than 220,000 people and displaced millions.The leader of the world's 1.2 billion Roman Catholics has also called for laws to end social inequality.In Cartagena, he will focus on the marginalized, particularly children at risk of sexual exploitation, often spurred by demand from foreign tourists.Francis is due to visit the impoverished neighborhood of San Francisco, where he will bless a shelter for at-risk Afro-Colombian girls vulnerable to child prostitution, drugs and violence.He will then meet participants in two charity programs and pray at the church named for Saint Peter Claver, renowned for his work helping slaves in the 1600s as they came off ships from Africa to be sold in Cartagena's markets.Some 300 Afro-Colombians who receive assistance from the Jesuit religious order, of which the pope is a member, will pray with him in the church that holds the relics of the saint known as the "slave of slaves.""Cartagena needs a lot of help," said Leonard Locarno, 29, a nursing student from the San Francisco quarter. "I hope he prays for all the people lost in vice, so that things can improve for them. There is no work here."Around Cartagena, a city of under a million people, hundreds of thousands, many displaced by Colombia's war, live in makeshift wooden shacks in slums with open sewers and no running water.Cartagena has been plagued by corruption scandals and a high turnover of mayors, exacerbating the divide between rich and poor.Later, the pope will say Mass in the port area, where he is expected to address human rights and social inequality in his homily.The walled city - which in the 16th century was frequently attacked by pirates - is now the preserve of tourists and luxury hotels, where the poor sell trinkets, coconuts and tropical fruits.Cartagena made headlines in 2012 during a visit by then-US President Barack Obama when his Secret Service agents were involved in misconduct with prostitutes in a hotel.The incident highlighted the few options available for women and girls who resort to the sex trade to put food on the table.