What if you could look at the source code behind any online visualization, check what data sources it uses, reproduce the results and modify any of its parameters? In this talk, I will present a data visualization project that I created around the Olympic games (http://rio2016.thegamma.net) which visualizes interesting facts about Olympic medals, but more importantly - lets you modify existing visualizations, interactively explore the data on your own and share your insights. Along the way, you will learn about building functional client-side web applications with F# and Fable – the F# to JavaScript compiler for 21st century. I will discuss how type providers change how we think about data, how functional types save the day and let you model complex domain (of data transformations) with a few lines of code and how immutability and functional programming make it easier to build interactive web applications (and what nice patterns can we learn from Elm)