Although the theoretical longest line of site in the UK is Snowdon to Merrick, at 144 miles, it is quite difficult to photograph due to a number of conditions needing to be right. But I have to say that the photograph of Snowdon taken from Bleaklow Head in Derbyshire at a distance of 96 miles is one of the best line-of-site photos I've seen on this subject. Link here: http://www.geograph.org.uk/photo/329077 The longest line of site that I've seen myself (although not photographed) is possibly the Isle of Man from Amlwch on Anglesey earlier this year (seen from sea level). I've also seen the Isle of Man from the top of Blackpool Tower. Stood on top of Winter Hill I've seen Blackpool Tower in one direction and Mow Cop in the other direction. And I've also seen the Wirral from the Cat & Fiddle near Buxton. A good source of what can be seen from where is Viewfinder Panoramas: http://viewfinderpanoramas.org/panoramas.html#england Anyone else got their own longest lines of site?