Deep-sea trenches are the deepest parts of the ocean, formed by the movement of tectonic plates. They occur where one plate is forced under another, creating a steep, narrow depression in the ocean floor. The Mariana Trench, located in the western Pacific Ocean, is the deepest known trench, reaching depths of about 36,000 feet (10,973 meters). These trenches are home to unique ecosystems and organisms that have adapted to extreme conditions, such as high pressure and low temperatures. Research in these areas helps scientists understand more about marine life and the geological processes that shape our planet, including the role of trenches in the Earth's tectonic activity.