The built environment plays a significant role in the decision to bicycle for transport purposes. It is also the primary barrier to introducing bicycling as a viable means of transport in developing urban mobility systems. As such, bikability—the relative-friendliness of a transport system to bicycling—is a topic of increasing interest among planners and policy makers. Identifying and quantifying the factors that contribute to a city’s bikability is essential to providing an evidence-base for efforts to create multi-modal, sustainable, healthy, and just transport systems. In this chapter, we identify, describe, and compare the built environment characteristics of a high-bicycling city to a low-bicycling city so as to make recommendations for improving the overall quality of the bicycling environment. With the advent of so-called big data (i.e., large amounts of publicly available, spatially referenced, and up-to-date information about the built environment), we have the opportunity to better understand urban environments than was previously possible. The potential is there to use big data and methods to understand urban bikability and provide clear directions for practitioners. This research aims to do just that, situating findings within social and political context, and offering directions for increasing urban bikability internationally.