This is a really cool tunnel that I like at Embankment Underground Station. The blue wavy lines as the stairs descend down the hole always catch my eye. Its a staircase that doesn't appear to be used much but did manage to get a passing passenger in my photo which I think adds a nice touch. I have been here before but not with my fisheye and again with the natural curves and lines already there, the fisheye does a wonderful job capturing them.
Oh on some other news, I have finally got round to buying Silver Efex Pro 2. Really looking forward to getting it, it should come today all being well. I got it from the UK Amazon for £129 which is far cheaper than anywhere else at the moment so if you are after getting it, try Amazon. :-)