Where do I find the Flatten Layer tool in Photoshop?

I can find the merge down tool, but I don't know how to flatten layers. If someone could explain it, that would be great.Where do I find the Flatten Layer tool in Photoshop?
If you have a PC press SHIFT + CTRL + E





-OR-





It's in the LAYERS menu at the very very bottom.





If it's not working for you, make sure all of your layers are turned on. (meaning, make sure the little ';eyes'; are clicked next to each layer) It won't flatten layers which are turned off.Where do I find the Flatten Layer tool in Photoshop?
on the version i have cs2. it is in the tool bar on top under layer and the second option from the bottom it has a flatten layer option.