Getting unknown property: craft\web\Application::GeneralConfig Sorry, rusty at PHP and learning Craft.

My code looks like this:

$url = craft::$app-&gt;GeneralConfig-&gt;siteUrl();


What am I doing wrong? I want to build a URL for some links in a plugin.
Please use a proper IDE or take a look into the source code to get to know the functions of the class. As you can see in the class reference the function is called 

Craft::$app-&gt;getConfig() 


However - in order to create urls you should use the UrlHelper