Is it safe to leave a crock pot cooking all day while I am away from home?

I've never used my crock pot before so I don't know if this is a stupid question or not. I've asked a couple of questions already and in some of the responses some of the answers say to let the food in the crock pot cook all day while gone at work. Is it safe to leave the crockpot on unattended while I am away from the house? And if so, where is a good place that I should place the crock pot while it is on and cooking for safety? Any help is appreciated. Thank You.