For decades, great white numbers were declining in the waters around New York but now the seals are back! Are the great whites far behind? Shark Week's Dr. Craig O'Connell tries to find the answers and shows the future with great whites in New York.

Across the world, sharks congregate and concentrate around volcanoes and volcanic islands. This year on Shark Week, Dr. Mike Heithaus dives several volcanoes to find out why they are shark hotspots?