American pop superstar Madonna on Tuesday took her four adopted Malawian children - David Banda and Mercy James, both 11, and twins Esther and Stella Mwale, four - back to their home country for the opening of a children's hospital that her charity built. Named after her adopted daughter, the Mercy James Institute for Paediatric Surgery and Intensive Care located in Blantyre, Malawi's second-largest city, is the first such facility built in the country by Madonna's Raising Malawi charity.