Why was the Atlantic coast called a graveyard?

North Carolina Outer Banks is well know for a very dangerous stretch of ocean known as the Graveyard of the Atlantic. This is an apt title given that over 600 ships have sunk off of this coastline. Absolute attention is required when passing through Cape Hatteras waters. Diamond Shoals extends fourteen miles out into the Atlantic and is comprised of shifting sand bars lurking shallowly under the waters off of Cape Hatteras. The strong currents and hidden shoals can pound a ship to pieces in minutes. The nonexistence of natural landmarks along this low lying flat coastline meant that ships had to draw dangerously close to shore to get a bearing.