Terrain of which less than 10% has been mapped

Once upon a time, a team of adventurous explorers set out to map the vast and mysterious terrain of a new continent. With their compasses and maps, they trekked through thick jungle, climbed treacherous mountains, and crossed raging rivers. But as they finally reached the shore, they realized that they had run out of time and resources, and less than 10% of this massive area had been mapped.

As they stared out at the endless expanse of water before them, one of the explorers had an idea. “We may not be able to map all of the land, but what if we accounted for the land that is already mapped and subtracted it from the total area? Wouldn’t that give us an estimate of the unmapped area?” she exclaimed.

The team quickly got to work, using their calculations to determine that the vast majority of the unmapped terrain was actually water – the great unknown depths of the ocean. And so, with a newfound appreciation for the mysteries that lay beneath the waves, they returned home with the answer to the crossword clue: “terrain of which less than 10% has been mapped” – the great OCEAN.