Pictured from left to right, President Hamid Karzai of Afghanistan, President Asif Ali Zardari of Pakistan, Bill Gates, co-chair and trustee of the Bill & Melinda Gates Foundation, polio survivor Ramesh Ferris, President Goodluck Jonathan of Nigeria, Wilfred J. Wilkinson, chair Rotary Foundation Trustees, and Dr. Margaret Chan, director-general of World Health Organisaton, at a high level event, ‘The Legacy of a Polio-Free World’, at the United Nations,Thursday, Sept. 27, 2012. The event highlighted progress and challenges in the effort to achieve global eradication of polio. (Stuart Ramson/Insider Images for UN Foundation)