Crop marks not going away

[emmy v]

I accidentally clicked a button and now these lines won't go away. The photo I have attached is a new file, I thought maybe that the issue was only on one design but now it's on all.  I did click the crop tool to see if it would go away and instead it made lines new lines on top of what was already here. When I deselected crop after that the original lines were still here . 

[emmy v]

These aren't even guide lines either. Does someone know how to get rid of them?

[Semaphoric · Accepted solution]

That is the Grid, useful for aligning vertical and horizontal objects. Command+'  (apostrophe) toggles its visibility. You can set it up in  Edit > Preferences >  Guides, Grid, and Slices.

Note that tis is not the same as the Pixel Grid, which shows if you zoom in far enough.

[emmy v]

Wow! Just the simple Command+' worked! Thanks!