Last October, on her Huge If True YouTube channel, Cleo Abram explored the state of deep ocean mapping, why it lags behind our mapping of, say, Mars, and what’s being done to chart the ocean floor at a higher resolution than currently exists (e.g. the Seabed 2030 project). All told this is a good and enthusiastic primer for the relatively uninitiated (though I do have to quibble with the statement that Marie Tharp’s maps have “largely been forgotten by history,” but then I’ve seen rather a lot about Marie Tharp’s maps and am a bit of an outlier).