Honestly, anything made by the BBC Natural History crew are all equally great. Planet Earth did a fantastic job of giving a general overview of the planet but it hardly scratched the surface of what's actually out there to be filmed. Frozen Planet II just recently came out and it's equally incredible, and Planet Earth III is supposed to come out soon, but there are a few hundred other nature documentaries by the BBC that don't get nearly the recognition they deserve, and a lot of the older ones have been re-scanned and released in HD like Attenborough's Life on Earth.

I think one of my all-time favorites is Life In The Undergrowth, filmed using macro lenses that make even the smallest insects incredibly detailed, an entire world we can't see with the naked eye.