Former president John Agyekum Kufuor arrived back home Sunday night after delivering the keynote address at the triennial World Congress of the Society for International Development (SID) in Washington DC, capital of the US.A statement signed by Frank Agyekum, his spokesperson, said the former President spoke on: “Our Common Challenge - A World Moving toward a Sustainable Future”, at the Congress attended by more than 1,000 of the 3,000-member SID spread over 80 countries.Other speakers included, Robert Zoellick, President of the World Bank, Donald Kaberuka, President of the African Development Bank, Kandeh K. Yumkelia, Director-General, United Nations Industrial Development Organisation and Gayle Smith, Special Assistant to the US President and Senior Director of the National Security Council. The Congress discussed a wide range of critical international development issues among them, economic progress, human development, health, governance and citizenship, science and technology.Former President Kufuor was away for about two weeks.