Compass and Map
You thought something out of the ordinary was in order for this year's vacation so you opted for an adventure tour in the Australian outback. It was all dingoes and kangaroos until your tour group pulled off without you after a lunch break. Now you're stuck with a ration of water, a map and the compass your best friend got you for good luck. It seems like good luck may be headed your way after all -- with these scant supplies and some modest orienteering skills you should be able to find your way back to the safety of your camp.
Compasses work by using a magnetized pointer along with the Earth's natural magnetic field to calculate direction. If you have a compass and a map of the area you can pinpoint specific locations and get wherever you need. If you're stuck without a map, but you still have your compass, you can at least get going in the right direction. Now that GPS is on the scene, compasses have taken a back seat. While a GPS may be better at pinpointing your exact location from any spot on Earth, it requires something you won't be able to provide in a worst case scenario -- a charged battery. In this case, the compass that relies only on the Earth's magnetic field is a better alternative.