March 23, 1875, the Challenger expedition collects a sediment sample (radiolarian ooze) from a depth of 8.184 meters near the Mariana Trench. The seafloor there lays at a depth of 10.994 meters and is the deepest point on Earth, known today as the Challenger Deep 🐟
https://www.nhm.ac.uk/our-science/services/collections/mineralogy/ocean-bottom-deposits.html?fbclid=IwY2xjawJM9QlleHRuA2FlbQIxMAABHdU9-ukyyY3wnEmY2Db2lNJ9VgUSg9PySvX2wbLFmDmsx8gVHR1BbyiUbQ_aem_UFZdiHhX5CbeuHZxUyhoCA