The deepest trench is greater than the highest mountain. Mount Everest is the highest mountain peak at 8.848 km, and the deepest trench is the Mariana trench which, at its deepest, is 10.911 km.
The surface of the Lake Superior is above sea level; the deepest part is about 600 feet below sea level.
Mauna Kea in Hawaii is the tallest mountain on Earth when measured from base to summit. While not the tallest above sea level, its base is located below sea level, making it the largest mountain below sea level.
mariana trench
The surface of the Dead Sea is 1388 feet below sea level and at its deepest point is 1237 feet deep.
600 feet if the mountain is already below sea level and so is the valley then just subtract the difference
The Dead Sea is approximately 997 feet (304 meters) deep at its deepest point, which is located in the northern basin. The depth of the sea can vary slightly due to factors such as evaporation and salt content.
It kind of depends on your definition of deepest cave :) It is usually taken to mean the greatest vertical distance from the cave mouth to its deepest explored point, so the deepest caves actually start pretty high up to begin with. The deepest known cave is Krubera in Georgia at over 2kms deep. It doesn't extend below sea level. However there may be other caves that are deeper, but not explored, and Krubera may well extend to below sea level, we just haven't found a way to get down that far (the limestone massif it is situated in extends below sea level and there have been tests releasing dye into the cave- the dye came out offshore in the black sea I believe). There are plenty of caves that do extend below sea level- all sea caves will have done so at some point.
treches. 300 km or below sea level.
The Andes is the longest mountain range in the world above or below sea level. I think the mid-ocean ridge is the longest below sea level...but I'm not sure
The deepest point is 3,742 meters [below sea level] and has a mean depth of 1,753 meters.
Dead Sea shore, Israel-Jordan: 1369 feet / 417.5 meters below sea level