A Swiss daily newspaper Tages-Anzeiger published an interactive map showing the spatial distribution of Swiss soccer fans using CartoDB, a data visualization tool. The map displays the municipalities where fans of nine top-flight clubs reside, with polygons colored according to the dominant club. To create this map, the developers collected and pre-processed data on season ticket holders from ten top-flight clubs, matched zip codes with municipalities, and used CartoDB's editor to style the map and calculate quantiles for opacity classes. The final application uses CartoDB.js API to build a standalone app that updates the CSS when a user chooses a club, displaying information about each club and municipality in tooltips or popups.