" Bog snorkelling" , so this is a very English kind of idea or British idea, the idea that you would go swimming through a kind of nasty, muddy, long puddle.
The Anangu Aboriginal people, part of the native population of Australia, said it was being destroyed by tourists permanently wearing down it's surface and polluting nearby water holes.
We invented grammar because without prepositions, we couldn't describe what it's like to fly through a cloud, or jump over a puddle, or Faulkner beneath the stars.