Beneath the waves, in a remote corner of the Indian Ocean, is the top of a mountain.
Rising from the seabed thousands of meters below, it is the Saya de Malha bank.
Scientists believe it's home to the largest seagrass meadow in the world - carpeting an area the size of Switzerland.
That's important because this vast aquatic wilderness of carbon-dioxide capturing plants could play a crucial role in tackling climate change.
It's the reason the Greenpeace ship Arctic Sunrise, with a team of scientists on board, navigated to the isolated spot - roughly located between the Seychelles and Mauritius.
But getting there wasn't easy.
The waters are relatively uncharted, and the wildly varying depths create, as University of Exeter ecology lecturer Dr Kirstin Thompson describes it, a "strange place".
"And if you imagine it's like a towering bank that comes out of the seabed, the seafloor around it is thousands and thousands of metres deep. So as those currents hit the edges of the bank, there's some very confused swell."
Once above the plateau, researchers got to work.
Seagrass leaves found floating in the water were collected for analysis, as well as samples to identify some of the thousands of species thought to thrive in the Saya de Malha ecosystem.
Crew member Alessander Montanari was the first in the water.
"It was simply amazing, lots of seagrass, corals, small schools of fish that find harbours in these corals and rocks. It's amazing, the seabed is almost covered with this nice seagrass and corals together."
A remotely operated underwater vehicle was deployed to record rare footage from deeper parts of the bank.
It's not clear how much carbon may be stored in Saya de Malha but studies suggest that globally seagrasses store more per square mile than forests.
"Most people acknowledge that we are in the middle of a climate emergency and we need to think about all the different ways that we can, all the different tools that we have at our disposal to try and avert this emergency and protecting these areas is one way of making sure that we're not making the climate emergency worse but also we have that ability and that valuable ecosystem in the future for future generations."
Seagrasses are thought to cover more than 100,000 square miles globally - but estimates are hazy due to patchy data, according to the United Nations' Environment Program.
The UNEP also warns that the equivalent of a soccer field of seagrass is lost every thirty minutes due to human activity.