Wait until web browser has loaded first page Visual Basic Net

I want to do a 2 step Source-Download-Process. So I have like

WebBrowser1.Navigate("http://ift.tt/1W5OMFj")

'HERE code for downloading and saving the source code of the site into a variable
'Directly after having downloaded the source, open the second site and do the same

WebBrowser1.Navigate("http://ift.tt/1SaORsZ")
'Download the Source code into one string variable

The problem is that my web browser will be loading two sites directly after each other very very quickly, not enabling me to download sources for both sites.

I tried everything, I googled "wait for browser to load one site" etc. and everything that has to do with while loops to see whether a browser has loaded a site it crashes my program.

What to do?