There's a good deal of argument about the short-term and long-term effects of this event, and I'm not about to enter the debate right now. Except to mention the really wonderful sound bite NPR ran this morning, wherein an official associated with the containment project (still ongoing; there can be no cleanup, but they keep piling cement on top.) asserted the excellence of the Soviet government's response.
...so what if they neglected to mention it to the downwinders?
But Time Magazine has placed twenty year's of coverage online. Remember what it was like when governments kept potentially fatal secrets from the world at any cost? Back before the End of History?
There was a lot of controversy through the blogosphere a few years back about the accuracy of some claims on Elena Filatova's Chernobyl website, such as the source of the photos. However, they're still stunning. And she's added some night photos, taken by motorbike headlamp.