We all depend on GPS in one form or another, be it on our cell phones to locate us on the map or our in-car navigation systems to get us to our destination. But what if suddenly GPS was unavailable and maybe for a very long time? Can you find where you are? Can you get to your destination? Now where did you put that paper map?
I would guess people would freak out if GPS went down. Look what happened when Facebook went down! Well, the US Navy is seriously considering that scenario and is now training their officers once again in celestial navigation. Check out the story.
SoCalGIS.org 
My dad went to the Naval Academy an had a class on using celestial navigation. In the 50’s he was on the Navy’s only EDD (Experimental Destroyer) based out of Florida. The ship’s Captain asked about the celestial navigation equipment and asked if the sailor in charge of it knew how to use it. The sailor replied that the equipment had never been taken out of the box. The Captain asked the sailor to see if he could figure out their location with it. My dad suggested that he help. Dad stayed up all night going through his Academy notes trying to remember how to work the equipment.
Dad said they were able to get an accurate reading on where they were.