Been working my way through the Blue Planet II episodes.
That wonderful mix of David Attenborough's sincere enthusiasm for everything he's talking about, some amazingly glorious shots, interesting marine biology, and some hit you in the heart moments (Note, whale mother holding her baby close, weeks after it had died and refusing to let it go).
The last 10 minutes of each episode is a "Here's how we did it" with behind the scenes stuff on filming and tracking wildlife in the depths of the oceans.