If you are talking about dry land that is below sea level, then these are a few examples...
The Netherlands (formerly called Holland)
Southern Louisiana
If you are talking about seas or oceans, then it's just about all if not all of them. Sea level is basically the top of the water, like where the water level meets the shore. Anything below that is below sea level. If it is a lake or a pond, then it may vary. Because the level of the land may also be above or below sea level depending on the location.
In some places Yuma is at sea level.
In some places Yuma is at sea level.
The air pressure is greatest at sea level.
The lowest land elevation on Earth is the shores of the Dead Sea, which lies between Jordan and Israel. The surface of the Dead Sea is approximately 1,407 feet (429 meters) below sea level, making it the Earth's lowest elevation on land.
New Orleans is a wetland and some places are below sea level.
if the land surrounding the sea is below sea level
The country that lies below sea level is the Netherlands. Around a quarter of the country's land is below sea level, with much of it being reclaimed from the sea through a system of dikes and pumps.
40 feet below sea level is the answer
The Dead Sea, located between Jordan and Israel, has the lowest land elevation on Earth at approximately 1,412 feet (431 meters) below sea level. Additionally, parts of the Netherlands, specifically the region known as Zuidplaspolder, also lie below sea level.
above sea level
10 feet
14.7 psi = sea level. 15.2 psi = 1671 ft below sea level