MouseDown And Effect Based On Location Of Mousedown?

how to view and populate a listview with a text file. Now I come seeking wisdom on how do create an effect based upon the location where a mousedown event occured.

Here is my example. (I like to give simple examples because it helps me learn rather than be given the answer and learn nothing).

I am working in vb.net, in a windows form. I have a map of Western Europe called picturebox1.

I want another form to pop up when a user clicks on a section of picturebox1. For example: I want a "Germany" form to pop up when the user clicks on Germany. And such for if France, Spain, Italy, Austria, England, Scotland, etc...based on the location of the mousedown event.

Historically, when working with a picturebox with sections that were rectangle, I would do little screenshots and overlay them over the picturebox and use that as a cheat.

The challenge here is that the countries are polygons and now I need to learn this for real. I am looking for a little direction on where to go to learn about a mousedown event that causes an effect based upon the location of the mousedown event.

This can be a challenge because each country is of different x, y location coordinates so I image I need to create an elaborate if or case statement to capture and evalute. However, I don't know how to acquire the coordinates of a mousedown.