Excel on a Mac, View hide window

[KevinJWalsh]

My wife was trying to hide a column, then selected View, hide window and the entire sheet disappeared.  When she tries to open it back up, it will not open.  Is there a way to undo the View, Hide window command on a Mac?  

[#2]

@KevinJWalsh Well, that would be Unhide from the same View ribbon. It will list the workbook(s) that were hidden by the "Hide" button.