INSILICO is a 'cyberpunk' city constructed prim by prim in Second Life. In general the cityscape of Second Life has yet to grab us with only smaller architectural projects such as those focused on by The Arch being of note. However, the movie below providing a 9 minute flythrough of the INSILICO build within Second Life, thankfully free of dancing avatars and such like, is certainly impressive:See http://insilico.ning.com/ for more details..
