1740's Appalachian mountain man reenactor, Len Boyer, demonstrates how to build a fire using flint and steel.  The steel strikes the flint producing a spark which is caught in a piece of charred cloth.

The spark is then transferred to the tinder (in this case, leaves).  The flame is ignited by blowing steadily on the spark.  Once flaming, the leaves are added to the twigs in the fire pit.