There is the end of the Death Tunnel, and there is the deepest point in Hungry Shark Evolution's Main Map (can only be reached with Tiger Shark or larger Sharks), where Enemy Big Daddy and Enemy Mr Snappy are very common.
A Turbine is located on Western Sea's surface next to Hammerhead Shark's spawn point. Western Sea is a mine-infested sea and it's very easy to die with smaller sharks by mines. There aren't many mega mines or ultra/death mines but it still is a dangerous water to swim in. It is also populated by stingrays. To the left of the Western Sea Sign (top picture), the area is very barren, and if you are playing as a high-end shark with extreme Health Drain Acceleration (due to playing for 20 minutes or more), you would not want to enter this area.