I know this has been spoken about before, but I don't know where it is anymore.

So, here are my questions:

• What are the metaphysical Towers of the Mundus (the names) and how many are there?
  
  
  
• When were they created? Please try and be as exact as possible.
  
  
  
• Why were they created and what purpose do they serve?

As always, any info would be appreciated.

You might want to start reading here: http://www.imperial-library.info/obscure_text/nu-hatta_nu-mantia.shtml
For your second question:
Adamantia: Circa ME 2500: Supposed date of construction of the Adamantine Tower on Balfiera Island in High Rock, the oldest known structure of Tamriel. Earliest historical date in unpublished Elvish chronicles.
The other towers follow after Adamantia. Hints as to when some of them were built are in above linked text.