Though most are harmless, certain jellyfish species can cause extreme pain and even death. — Paul Souders/Getty Images

En español | When we travel, we tend to worry about the more obvious and extreme dangers — plane crashes, hurricanes and the like. But the worst traveling dangers can actually seem quite innocuous. You need to know about them so that, with a little forethought, you'll be able to avoid the potential harm they can cause for you or your family.

See also: How to help a drowning person.

1. Rip Currents
Did you know that most ocean drowning deaths are due to rip currents?

Rip currents are strong channels of water that can pull swimmers in, no matter how strong the swimmer. They don't pull people under water, but rather pull them away from shore. Unable to fight the current, swimmers can find themselves in major trouble due to exhaustion and panic. The scary thing is, this can happen even in knee-deep water or in a large lake.

Always swim with a buddy and never swim near jetties and piers, where those rip currents are fixed.

If you get caught, don't fight against the current because you probably won't win. Instead, swim parallel to the beach until you're free, or tread water until help arrives. If you see someone who needs help, do NOT attempt a rescue or you may be pulled in yourself.

Next: Jellyfish. Beautiful but deadly. »