If you're lost, walking downhill raises your chances of finding help.

People often build societies around nearby water sources, Ernest W. Adams says. And since water flows downhill, you'll increase your chances of finding help if you're able to walk downhill.

Adams references the example of Juliane Koepcke, a plane-crash survivor who floated down a river for nine days in 1971 before finding a boat and shelter. Several hours later, she was rescued.