The Greenstone Digital Library Software has helped spread the practical impact of digital library technology around the globe. As Greenstone enters its third decade, this article takes are newed look at its development, the challenges that have been faced, and the lessons that have been learned in deploying a comprehensive open-source system for the construction of digital libraries internationally. In particular, we outline architectural changes in the software that have occurred over time, and highight how the user interfaces have evolved to provide a more immersive,interactive user experience, made possible through advancements in the underlying web technologies.