We lived on a remote African farm with no power. 
Making bread each week was costly in Bottled gas.
So I made a Bread Oven.
We made a fire in it until it was very hot.
We put the loaves inside and bricked up the entrance .
After about an hour the bread was done.
The only cost was for a box of matches, for in those days, I didn't know how to strike a light, from a flint and steel and in those far-off pre-Ray Mears days a bow drill was quite unknown.
The oven was simple to make. I used an oil drum as a former to make a circular brick tower . When the mortar was set I removed the drum.
A couple of bars across the top and a sheet of tin held a 2" layer of cement to make the oven floor.
A sandcastle made the former for the oven itself. [a bit like making an igloo!]
A hole in the top for a chimney and a square entrance at the side.
When the mortar was set, the sand was removed and the oven was ready.
