Clarification - in the past when I've written high performance data tools in JS, it was almost entirely to support the use case of needing it to run in a browser. Otherwise, there are indeed more suitable environments available.
To your question, I was about to point out Firefox[1], but realized you clarified 'mainstream'[2]...
Getting a broad overview of "world history" is useful for having basic context for large events, but, IMHO, history gets so much more interesting and educational when you're deep into individual people's lives and stories. I'm probably a bit biased, but tend to agree with the suggestions that you pick a time and place and dive deep into an individual or event that catches your fancy.