1. If you get stuck in riptide, remain calm and swim parallel to shore. Swimming to the shore will just tire you out faster.
2. When crying for help, call out specific people (eg. "you with the green shirt!"). It makes people more likely to act and not be affected by the bystander effect.
3. In survival situations, while it will change depending on your body, remember the rule of threes:
3 minutes without air (maybe you're buried in snow following an avalance)
3 hours without shelter against the elements
3 days without water
3 weeks without food
4. Most phones are able to dial 911 even without service or a SIM card.
5. Additionally, 112 is the international 9-1-1 in most places.
6. If you see a photo of yourself (or anyone else - particularly children) where they only have one 'red eye' from the flash, this could be a sign of neuroblastoma (a type of eye cancer).
7. If caught in a burning building, get low. The breathable air will be near the floor.
8. Learn the self-Heimlich.
9. Do you have a desk job? Be sure you get up at least once every two hours and walk around for 5-10 minutes. Doing this reduces the chance of developing blood clots in your calves.
10. If you're a man and you pee on one of those pregnancy test, if it comes up positive you may have testicular cancer.
11. Just because the light turns green doesn't mean its safe to go.