Ocean trenches are deep, narrow depressions in the ocean floor, formed by tectonic plate movements. They are the deepest parts of the world's oceans, with the Mariana Trench being the most famous, reaching depths of about 36,000 feet. These trenches are often associated with subduction zones, where one tectonic plate is forced under another. These underwater features play a crucial role in Earth's geology and ecosystems. They are home to unique marine life adapted to extreme conditions, such as high pressure and low temperatures. Ocean trenches also influence ocean currents and the global climate by affecting the distribution of heat and nutrients in the ocean.