A visualisation of the northern European airspace returning to use after being closed due to volcanic ash. Due to varying ash density across Europe, the first flights can be seen in some areas on the 18th and by the 20th everywhere is open.
The flight data is courtesy of flightradar24.com and covers a large fraction of Europe. There are a few gaps (most noticeably France) and no coverage over the Atlantic, but the picture is still clear.
Cities can be considered "flows of people, vehicles and information" (Sheller, 2004) transported along diverse urban networks. In this Flowprint of London, the city's extensive bus network is used to sketch an animated portrait of the living city.