This presentation summarizes the scientific literature on the impact of science centres on their respective communities, with a focus on learning and education, local economic development and community development. These effects contribute to the goals of the Mechelen Declaration, approved at the 2014 Science Centre World Summit. Science centre visits also deepen the learning process, enhance motivation, strengthen confidence in science, affect attitudes towards it and influence career choices. Every year, they host more than 300 million visitors worldwide, with a total economic impact in the range of 7-20 billion USD. Science centres have been instrumental in many urban redevelopment schemes around the world.