Grid lines on pdf

[#1]

A while back I was working in Adobe and I must have clicked something to cause the grid lines to show up on the adobe pages.  They are a bit distracting and can make it hard to read documents.  Does anyone know how to remove these grid lines?

See below for an example. 

Thanks-

[ls_rbls · Accepted solution]

You can hit CTRL+U key combination to toggle them on and off.