How to stop navbar from wrapping to a second line when resized, like FB navbar?

My navbar overlaps/wraps to a second line when the screen resizes/reduces. This looks messy. I have used a toggle button for media devices, but this doesn't address the issue of when people resize the window.

There are two websites I can give an example of what I am hoping to achieve with my navbar/page:

1. https://www.facebook.com/
2. http://www.dailymail.co.uk/home/index.html

Note with both of these websites, that when the screen is resized, the page remains the same; although the window is reduced, nothing on the page is reduced. The navbar remains the same.

This is what I would like to achieve, but I'm not sure how?

And is it possible to achieve this with just the menu/navbar? Rather than making the whole website fixed in position?

All replies will be much appreciated!

Thanks!

John.