While we experience our cities in 3D, how we have visually made sense of and planned them has traditionally been in 2D through maps, plans, and spatial models and statistics. When we have visualised cities in 3D as architectural drawings or photographs it has largely been from fixed views from particular vantage points. These limitations are in the process of being overcome through the development of new 3D geospatial technologies such as virtual reality (VR), augmented reality (AR), building information modelling (BIMs), city information modelling (CIM), and the creation of new 3D spatial data such as lidar scans and 3D models digitised from stereoscopic images. These technologies and data have the potential to significantly disrupt administrative, planning, architectural, construction and real-estate practices, by enabling users to immerse themselves in, explore, interact, query, and experiment with spatially-intelligent virtual environments, or to overlay data using head-mounted displays onto real-world locations while in situ, creating greater understanding of a location, better decision- and policy-making, and improving operational efficiencies. They are also vital to the functioning of autonomous vehicles, enabling safe navigation of city streets, and have application for infrastructure management, particularly those that are hidden in conduits in walls or located underground. In addition, they enable the creation of new information and entertainment apps utilising 3D spatial data (such as Pokemon Go). In this short essay, I briefly outline each of these technologies, detail their disruptive potential as part of a wide move towards the smart city, and consider some of the politics of their deployment.