Once upon a time, your ancestors used to look at the night sky to determine their location. Then we used a Thomas Guide, remember those? Today, it only takes one magical technology to get driving directions, send your picnic spot to a lost friend, or track how far you’ve gone during a workout. That technology is called GPS, and you’re about to find out the secret behind it. 

Did you know that GPS was actually a military invention? The highest quality signals were only used for military purposes until May 2000, when it became available to all civilians for free. Now GPS is literally everywhere, and you can now even purchase GPS insoles to keep track of your kids or relatives with Alzheimer’s disease. 

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