How you you picture the INTERNET? Where is it? What is it?

Having heard a fascinating discussion on CBC how people in various accomplished fields describe how they picture the INTERNET, I was amazed at the range of responses.

Where is it? In space? In the sky? Underground?

What is it like? Is it like a cloud? Is it a big machine somewhere? Is it at your cable or telephone company?

Please describe how you picture it and how you imagine it work.

I would sincerely request that Internet Wizards hold back from demonstrating their technical wisdom until others have described their impressions.