Sustainable cities?

What do you think of when you read the term Sustainable City?

I like this:

The Living Building Challenge:

“Imagine a building informed by its eco-region’s characteristics and that:

• generates all of its own energy with renewable resources
• captures and treats all of its water
• operates efficiently and for maximum beauty”

and this:

"Imagine Cities that could:

• play a beneficially role in their local ecosystems
• generate all their own energy from renewable resources
• produce the majority of their own food
  
• operate both efficiently and with maximum livability and equity"

read more at Open Alex