 Complete the following phrase:  Throughout his career, Messi has been involved in charitable efforts aimed at vulnerable children, a commitment that stems in part from the medical difficulties he faced in his own childhood. Since 2004, he has contributed his time and fices to the United Nations Childrens Fund UNICEF, an organisation with which Barcelona also have a strong association. Messi has served as a UNICEF goodwill ambassador since his appointment in March 2010, completing his first field mission for the organisation four months later as he travelled to Haiti to bring public awareness to the plight of the countrys children in the wake of the 