I grow in a warm country full of beaches, corn and volcanos, our childhood was great when our parents used to take us out of the city for vacations, chasing lizzards and climbing on mountains of corn.
One of those summer days my mother decided to take all her 9 kids to do a little "climbing" up to an inactive Volcano, the "Nevado de Colima" up, up, up, we went, but we never saw the top, no water, no food, broken shoes, getting dark and suddenly... a hunters truck! They looked at us with eyes wide open, and a surprise expresion on their faces, then they asked us: "Where are you going?" and my mother answer them: "Up!", and that single word would be enough for the hunters to realize we were in the wrong volcano, and this volcano in particular, was an active one and full of dangerous gases in the top. We went down , down, down and the next time my mother take us to do volcano climbing, she always made sure it was an inactive volcano!
When I was little I always wonder how volcanos "function" I had a Geology class afterwards, so to know and explain even to a kid everything about Volcanos, I found this french link quoting a larousse explication on the web, is in french and is excelent!