The maximum known depth of the sea or ocean on Earth is located in the Mariana Trench in the western Pacific Ocean. This trench is the deepest part of the world's oceans and reaches a maximum depth of approximately 10,925 meters (35,843 feet) at a location known as the Challenger Deep.
The Mariana Trench is a crescent-shaped trench located east of the Mariana Islands. It was named after the nearby Mariana Islands and was first measured in 1875 during the Challenger Expedition, which gave rise to the name "Challenger Deep" for its deepest point.
To put the depth of the Mariana Trench into perspective, if Mount Everest, the highest peak on Earth, were placed at the bottom of the trench, there would still be over 2 kilometers (1.2 miles) of water above it.
It's worth noting that our knowledge of the ocean depths is still evolving, and new discoveries can potentially reveal even deeper areas in the future.