Important tools that schools need to support a 21st century approach to teaching and learning include the usual suspects: the Internet, pen and paper, cell phones, educational games, tests and quizzes, good teachers, caring communities, educational funding, and loving parents. All of these items and more contribute to a 21st century education, but two key tools not on this list may be the most powerful learning tools ever devised: "questions" and the process to uncover their answers, and "problems" and the inventing of their possible solutions. Questions have long been the motivation for discovering new knowledge in science, and problems have been the inspiration for inventing new ways to live and work through engineering and technology. In this article, the author explains the significance of inquiry and collaborative learning methods to the process of teaching children how to learn. He stresses that inquiry- and design-based projects rooted in driving questions and real-world problems can be the key to unlocking increased student motivation and engagement, deeper understanding and effective use of knowledge, and the mastery of 21st century skills.