With the rise of human pluripotent stem cells and ever-improving differentiation protocols, we now have a powerful tool to explore human-specific aspects of brain development and function. In this talk, I will first give an overview about how we differentiate stem cells into 3D tissues (commonly known as neural organoids) that mimic human brain development and function. I will then share two examples of our recent work, in which we recapitulate brain region interactions. First, I will discuss how we have modelled interneuron migration by fusing organoids that represent distinct brain regions. Then, I will present work in which we re-grew the human dopaminergic system using a ventral midbrain : striatal : cortical differentiation strategy and spatially assisted fusion. Finally, I will discuss ongoing research in the Stevens Group and how we think these technologies, together with the enormous capabilities of bioengineering, can shape the future: from a fundamental understanding of human brain development to function, disease modelling and translational trajectories.