Wondering what could be lurking at the bottom of large bodies of waters is a topic that may keep you up at night.
But thankfully, there are some people who are brave enough to explore the seabed in the name of science.
The bottom of the water may be more familiar to humans than we think, as it's the site of an 8,000-year-old civilisation.
Scientist Albert Lin waded through the bitterly cold waters to track down the ancient metropolis just off the Isle of Wight.
The Channel is a notoriously difficult place to dive due to its freezing temperatures and powerful tides.
After dropping below the surface, the team made their way towards the treasure trove of information 'from another age'.
As part of his Lost Cities series in 2019, Albert teamed up with maritime archaeologist Garry Momber for the mission.
He quickly began to find signs of former life just minutes after entering the cloudy and cold water.
Albert exclaims: "Is that a tree? There's a tree down here! Wow."
Although it's hard to imagine, the English Channel's now-seabed was actually dry land 8,000 years ago.
The sea levels were much lower at the time and the UK was still physically linked to Europe.
Somehow, the wood Albert spotted had survived underwater for a millenia.
The divers then continued their search and incredibly stumbled across 'some kind of structure' at the bottom of the Channel.
Underwater video shows several layers of wood intertwined together, which Albert suspects may have been a dock.
"It feels like we are sitting in an ancient ghost town, but underwater," the scientist said.
He then grabbed a small sample of the structure to take back to the boat for the team of boffins to analyse.
After surfacing, Albert gushed: "That was incredible.
"Looks like there's a whole platform down there. It's layered, one piece on top of the other, almost like a dock.
"Its cold down there and murky. But it's incredible!
"You know, you descend down this line and out of the darkness comes the ancient past."
Garry suggested that the site was largely used for boat building, fishing, hunting and collecting reeds.
The pair then began to assess the wood that was 'locked in time', with the ocean expert explaining how it ended up there - and how it had survived.
He explained: "As the sea level has risen above it, it's covered it with this slit and its taken away all the oxygen.
"It's just preserved it in a sort of anaerobic, oxygen-free environment. It would have stayed there for many more thousands of years - but recently, the old landscape's eroding away, which is how we found this."
The maritime archaeologist said finding composite structures like this was of 'international significance'.
"It's 8,000 years old," Garry said. "You don't just get these everyday."
He suspects that the wood was situated next to a stream - pointing to the fact it may have been a platform or pontoon.
"We don't know because there's nothing else like it in the country," Garry added.
"And somewhere we found what we believe to be the oldest boat building site in the world, where they would have built a canoe, a long boat. So that's what they would have sailed."
It certainly trumps the rusty shopping trolley or the unexploded WW2 grenade dumped in the local canal.Featured Image Credit: National Geographic/AI artist Ralph