http://www.vh1.com/video/metal-evolution/full-episodes/thrash/1676889/playlist.jhtml
This is the Thrash episode of Metal Evolution on vh1 classic. For a huge fan of the genre as a whole I really enjoyed it and thought they did a good job. I posted it here because even though it's 45 minutes or so and it covers the entire genre, a good ~15 minutes (total, not at once) are dedicated to Metallica since they essentially created AND helped kill the genre.
What really caught my attention was when they started talking about the decline of the genre in the early 90s and The Black Album. I know thrash fans hate the album and considered it "selling out", but I didn't know the actual bands were split on it. You can see in the video it's pretty obvious how much Slayer hated it but Testament loved it. They interview a lot of thrash legends (like Mustaine, Lars, Kerry King etc) but
what was curious is that pretty much all of them except the Slayer guys admitted that Thrash became stale in the early 90s. They kept advancing with every album until finally they hit a wall and they noticed they couldn't do much more without copying themselves. Lars admitted that's why they wanted to change.
I don't know I watched the whole thing and was fascinated until the last 5 minutes when they quickly focused on the new age "thrash" bands that I have no interest in at all.