To give you a brief look at why I feel Akira is one of the most astounding accomplishments in filmmaking, animation and artistic history, I've created a quick two minute video which sums it up quite neatly, I think:
No other film has ever looked like Akira, before or since. It’s stunningly fluid and detailed animation often required as many as nine separate cel layers. The 125 minute feature was comprised of over 160,000 cels and almost as many backgrounds, each one completely hand–drawn and hand-painted. Purists recognize Akira as the last completely hand-created animated feature, as cel animation quickly gave way to cheaper digital production and CGI technology.
This is an example of a key setup - all layers of book and backgrounds, with a cel from the sequence. Click for high res version.