Province Bonus to Magic School?

[Kobal2]

What Jarkko says. Moreover, this is all stuff that remains firmly under the table : no one is wiser that you're breaking the bank, because wished gems/gold do not show up on the graphs. Which means that you can get very, very powerful while appearing to be non-threatening. The exact location of the site also remains a secret because unlike blood/conj sites it isn't spawning an ungodly amount of units every turn.

Also bear in mind that the longer your Wish machine remains active, the more powerful it becomes. It's a self-improving feedback system. Which cannot be said of other similar sites : conjuration, construction and blood reduction sites let you do more with less, but it's a linear function based on how many gems you're taking in. Discount wishing is exponential.