Deep Within Atlantic

Three quarters of the planet Earth is covered by water. A majority of the planet's solid surface is abyssal plain, at depths between below the surface of the oceans. The solid surface location on the planet closest to the center of the orb is the Challenger Deep, located in the Mariana Trench at a depth of. Although a number of human activities are conducted underwater; such as research, scuba diving for work or recreation, or even underwater warfare with submarines, this very extensive environment on planet Earth is hostile to humans in many ways and therefore little explored. But it can be explored by sonar, or more directly via manned or autonomous submersibles. The ocean floors have been surveyed via sonar to at least a coarse resolution; particularly-strategic areas have been mapped in detail, in the name of detecting enemy submarines, or aiding friendly ones, though the resulting maps may still be classified.