The show, this week focusing on the continent of South America, showed us incredible footage of animals living near volcanoes in the Andes to those who inhabit the world's largest rainforest - the Amazon.
We saw everything from a puma hunting her pray to crowdsurfing penguins, but among all the jaw-dropping scenes, there was an underpinning of sadness, as David's commentary revealed we were taking over these animals' habitats at an alarming rate.
The documentary stated that - alarmingly - we're destroying an area of forest the size of a football pitch every five seconds.
And the devastating affects of deforestation were shown on screen, made all the more sad after we learnt that animals like the adorable Cotton Topped Tamarind Monkey now only had roughly 100 families left in existence.
Reacting to the painful footage, one person wrote: "10 minutes into Seven worlds, one planet and I'm sobbing like a baby".
While another added: "@BBCEarth @BBCOne should come with a health warning. Such beautiful but heartbreaking scenes. Another outstanding series thanks to the incredible dedication of the producers, photographers, videographers, music editors etc".
A third agreed: "I'm feeling particularly emotional tonight. The combination of the amazing footage and how sad it is with the animals habitats disappearing is making me well-up #SevenWorldsOnePlanet".
"Catching up on #sevenworldsoneplanet. Amazing and heartbreaking again. Something has gone really wrong with humans, when we've lost such a disconnect with nature that we let these beautiful forests be obliterated," another viewer wrote.
Despite the overwhelming sadness of the episode, as per, there were some light hearted moments, too.
For one, we saw a group of penguins off the coast of Peru who found a rather clever way to navigate themselves over a pack of sea lions.
Realising there was no other option, one brave penguin led the way in clambering over the intimidating creatures, and was soon joined in the crowdsurfing mission by its peers.
It took mere seconds before people were making memes out of the penguin pups, and flocking to social media to crack jokes about them.
"Those penguins on #sevenworldsoneplanet are like the drunkard trying to get through the crowd to get to the bar!!," one wrote.
As another added: "Loving that penguin's sass".
Animals really are amazing, aren't they?
- A Perfect Planet: Viewers Left Heartbroken After David Attenborough's Urgent Plea To Save The Planet
- 'Seven Worlds, One Planet' Has Fans In Tears As Baby Albatross Abandoned
- New Trailer Drops For David Attenborough's Jaw-Dropping New Show 'Seven Worlds, One Planet'
- Sir David Attenborough To Present New BBC Nature Series ‘A Perfect Planet’