I just googled it, and the LOTR trilogy apparently has a total of 480,000 words, which brings home how huge 1M is! It'd be fascinating to see how well Gemini could summarize the plot or reason about it.

One point I'm unclear on is how these huge context sizes are implemented by the various models. Are any of them the actual raw "width of the model" that is propagated through it, or are these all hierarchical summarization and chunk embedding index lookup type tricks?