This hugely impressive map by Bruno Imbrizi is a visualisation of where every single train is on the London Underground.
The very clever and very hypnotising creation is based on the huge amount of data released by Transport for London (TfL) for developers.
It means the animation is in (almost) realtime as it is based on predictions for the next 30mins from TfL.
While there are a number of apps that show you when and were trains are, none do it such a beautiful manner.
You can choose individual lines or a combination of any of them - it also has a really cool "tube soundtrack".
Obviously, as this is based on geographical data, it is a great little glimpse into the actual layout of the Tube lines rather than the schematic shape we are usually used to.
Be careful though, it's really easy to get very lost in this...