Put on your thinking caps, have as many guesses as you want – and most of all, have fun. Your time starts …. NOW!
Spoiler alert: do not read any further unless you want to see the answer.
First part of the question: solved after 90 minutes by UK-based Alixzandra, who correctly identified it as (very tiny) anti-slip safety nubs attached to the surface of a train platform. I shot this at Richmond station yesterday, on a grey, drizzly morning!
Second part of the question: According to the Harry Potter tales, the magical train Hogwarts Express travels between London and which other station? Solved by US-based Maxy, who correctly answered Hogsmeade.
I do not crop, enhance or post-edit my images in any way. Shot with a Pentax K100D, using a Sigma 18-125mm lens. F8, 1/250 sec, ISO 400, focal length 125mm.
Featured in CONTRASTING PERCEPTIONS, May 2010.