NEST is a simulator for large-scale spiking neuronal networks with a history dating back to the late 1990s. The definition of what is considered a large-scale network has changed since as ever more powerful HPC facilities have become available. Contemporary supercomputers even provide the resources to represent brain-scale spiking neuronal networks. However, in order to enable neuronal simulators to exploit such resources, simulation code had to undergo fundamental design changes. Today, NEST works efficiently for a broad variety of models and on various platforms, from laptops to supercomputers. In my talk I will give an introduction to the NEST simulator and review the technological advances of the last years that have made NEST such an extremely scalable simulation tool.