I warn you now that if you're easily moved to tears by disturbing pictures then you may not want to watch this photo essay. Its a brilliant photo essay and well worth watching but it is very moving and very powerful. It does require sound for the commentary.
http://todayspictures.slate.com/inmotion/essay_chernobyl/
http://todayspictures.slate.com/inmotion/essay_chernobyl/