This article explores the concept of STEM education and characteristics of truly authentic STEM learning experiences and events. It examines the engineering design process and how engineering glues science, mathematics and technology together. Two engineering challenges, 'Design and build a bridge' and 'Design and make a catapult', carried out with students aged 14-17, are described. Evidence gathered throughout the activities showed that engineering challenges have many educational and social benefits. However, to embrace an integrated approach to STEM in our classrooms and during outreach activities, high-quality STEM teaching materials are needed along with well-informed professional development.