User check-in activity heatmap of London in the days before (left) and during (middle) the UEFA Champions League Final. Darker shaded regions denote a higher number of check-ins closer to the observed maximum among all regions during the same day. The size of the location markers in the rightmost figure is proportional to the number of check-ins at the place. Notice the significantly increased activity at the Wembley area in Northwestern London on the 28th of May 2011 when the UEFA football match was held (middle, right).