The world's largest rubber duck—a conceptual artwork by Florentijn Hofman—has just arrived in Hong Kong. More on Colossal: http://www.thisiscolossal.com/2013/05/the-worlds-largest-duck-arrives-in-hong-kong #Rubber_Duck
It's called the continental shelf. Depending on the area, you can have a continental shelf that cuts off shorter than others. These areas make wonderful places to snorkel because you can see deep down yet still be able to reach land rather quickly.