This is a research project and goal is understanding urban mobility through the visualization of the use of public transport systems. We focus on the visualization of anomalies regarding the number of passengers. To find patterns of use we analyze the raw data, which contains people counts for every bus stop in Coimbra city with half hour interval. For each stop, and for each day of the week, we calculate the average number of passengers and its standard deviation in each 30 minute interval. This allows us to identify situations that deviate from the norm.