Warning signs exist to make sure we don't go places or do things that could get us killed. But humans can be pretty stupid, and sometimes the signs have to ratchet things up a notch to make sure we get the message through our thick skulls. These 28 signs aren't playing around, and they make sure that we know exactly what we need to know. 

Many of these refer to hiking or swimming; things able-bodied people think they can do better than they really can. "Are you fit and adventurous?" one Grand Canyon sign says. "You fit the profile of three deaths a year." Other signs on this list keep a rolling death counter to show you the continued danger. 

We won't be proceeding past any of these, and we hope you won't be either.