Follow these instructions:

• Each cluster represents a group of markers. Click on it to zoom in and show all the markers inside of it.
• Each marker represents a location where a graffiti was spotted and is still there.
• Each marker represents a location where a graffiti was spotted but later got cleaned.
• To see the information related to the graffiti at a location, just click on the associated marker.
• Click and hold it in order to drag the map.
• Click home or hit "F5" to refresh the page.