Excel 2007 Column/Row Hide/Unhide Bars

I was working in an Excel 2007 spreadsheet and must have hit a unique key combination that caused bars to appear above and to the side of my spreadsheet. Clicking on them causes rows and columns to hide/unhide.

I can still work with the spreadsheet but the bars take up a lot of space and I would like to get rid of them. I have searched the Internet and through the menus but since I have absolutely no idea what this "feature" is called, I don't know how to get rid of it.

I have attached a picture of what I am seeing. Does anyone know how to turn this off?

Thanks.

John