Celebrate National Dog Day With This Quiz on Man's Best Friend

— -- On the ABC News app? Click HERE to watch this interactive video.

It's National Dog Day today, and to celebrate, ABC News went to a dog park in Los Angeles to quiz people about dogs.

Take the interactive quiz above to see how much you know about man's best friend.

Questions in the quiz include:

-Which of the following dogs has a star on the Hollywood Walk of Fame?
-What is the most popular breed of dog in the U.S., according to the American Kennel Club?
-What is the speediest dog, running as fast as 45 mph?
-What dog often has six toes?
-The most expensive dog to have reportedly been bought was a Tibetan Mastiff for around $1.5 million in what country?