If you are looking for a description and history of every major discovery in atomic and subatomic physics for the last century this sight is for you. The majority of the sight is set up in a tour format, and includes everything from radioactivity to annihilation to a brief description of quantum mechanics. All descriptions are qualitative and assume no prior knowledge of physics or math, yet still manage to be relatively satisfying.
My favorite feature is that the welcome and home pages both contain links to several articles on current research in the field. Once you have developed some sense of the subject by reading through the body of the sight you can come back and read about some of the most recent developments in more depth.
The only complaint I could think of is about the format. The particle adventure is a lengthy one (I lost count after, 2 hours and 50 pages) and it would be nice to have a linked index on, or linked to the homepage, in addition to the back/forward arrows on each screen. This is however a small issue and should by no means dissuade anyone from visiting this sight. Overall it is a very informative and well constructed sight.
It is apparent from the start that a lot of time and skill went into the construction of this sight. The page layout is aesthetically appealing and there are several interesting Java script animations. I found that the page layout was more than a little cramped when viewed with Netscape 6.0, though older versions of Netscape seemed to work perfectly.