This document discusses strategies for developing large, multi-stakeholder science engagement programmes on the natural world. It advocates using convening power to bring together diverse partners around shared interests and objectives. The goals are to inspire sustained public engagement with nature through collective reach, legacy outcomes, and positioning statements supported by empirical evidence. Examples provided include Darwin200 in 2009 and International Year of Biodiversity in 2010, which engaged over 450 partners in 1300 events reaching over 420 million people. Key lessons focus on the need for central coordination, independent monitoring, and addressing changing societal perspectives.