Closely related to the sovereignty problem is the challenge of international cooperation. The international landscape is diverse and complex, with more than 175 initiatives, funds, agencies, and donors (http://bit.ly/1KsNeCr). The UN has formed a health cluster led by the WHO (http://bit.ly/1FkxD1u), with 32 partner institutions (both inside and outside the UN), national governments, and civil society. Beyond the health cluster are multiple actors, including public/private partnerships (such as Gavi and the Global Fund), private industry, international charities (such as Médecins Sans Frontières) and health ministries, among many others. And, of course, public health goes well beyond the health sector, spanning agriculture, migration, trade, climate change, and much more.