Quicksand

Where one might find quicksand, I am not sure, but maybe that's why I'm worried about it.

UPDATE:
I was sufficiently curious about where exactly to find quicksand to do some investigating. This is what I found out:

Quicksand is not quite the fearsome force of nature that you sometimes see on the big screen. In fact, quicksand is rarely deeper than a few feet. It can occur almost anywhere if the right conditions are present. Quicksand is basically just ordinary sand that has been so saturated with water that the friction between sand particles is reduced. The resulting sand is a mushy mixture of sand and water that can no longer support any weight.

If you step into quicksand, it won't suck you down. However, your movements will cause you to dig yourself deeper into it. In this article, you will learn just how quicksand forms, where it's found and how you can escape its clutches if you find yourself hip-deep in it.

Quicksand is typically not very dangerous, but it’s one of the last things you’d want to run into if you were sandboarding. Check out the sandboarding article, video and images at Discovery’s Fearless Planet to learn more.

So, remember, if caught in quicksand DO NOT STRUGGLE.

Here's a link to where I found this helpful info: http://science.howstuffworks.com/environmental/earth/geology/quicksand.htm