Flowchart on the Use of Articles

Here is a simple flowchart to help determine which article to use.
This flowchart covers the general rules and does not deal with the details, special cases and exceptions.

Arrow Pointing Right Yes Arrow Pointing Right
Use "the"
I visited the Great Wall of China.
The apples I bought today were rotten.
Arrow Pointing Down
No
Arrow Pointing Down
Arrow Pointing Right No Arrow Pointing Right
No article
I need (some) water.
Arrow Pointing Down
Yes
Arrow Pointing Down
Noun singular?
Arrow Pointing Right No Arrow Pointing Right
No article
Footprints were found at the scene of the crime.
Arrow Pointing Down
Yes
Arrow Pointing Down
Use "a" or "an"
accordingly
She lives in a big house.
She bought an apple at the convenience store.