In Helsinki, a public, outdoor installation called CityWall allows multiple users to explore images and video tagged with "Helsinki" on Flickr and YouTube using a multi-touch interface.

The CityWall is designed to support the navigation of media, specifically annotated photos and videos which are continuously gathered in realtime from public sources such as Flickr and YouTube. To contribute content to the CityWall please send pictures and videos via MMS or email to post@citywall.org. Alternatively, tag your media on YouTube or Flickr with 'Helsinki' and we will pick up your media and display it here on the CityWall.

[via New Media Initiatives Blog]