An oil drum (barrel) and a bit of metal pipe is all you need to make a really simple but effective pizza oven. It may not look very fancy but it works well and it will cook a whole lot of pizza. Also, instead of waiting for days/weeks for your clay oven to dry enough to use, an earth oven can be made and used on the same day.The soil/earth/stones are vital to keep the heat in – but you could use sand, clay or bricks too. (Don’t use bark mulch or anything similar as it will catch fire for sure.) On our oven the soil ended up being around 8” thick at the top – which was good but more than was really needed. (We would have built the whole thing into a bank, which would have saved a lot of work, but there wasn’t one handy.) I would suggest you aim for 6” minimum.The chimney pipe isn’t essential – the fire would burn anyway – but it makes controlling the fire easier. You need a hot oven which means a fast burning fire. Take it down or block it off when the fire is out to retain the heat.Fuel – small section dry branches are best for a fast, hot fire. You don’t want a smouldering cool fire, so perhaps your very first job is to prep your fuel and leave it to dry somewhere.You don’t need a wooden door – you could just use the drum lid – but timber is an insulator so it should keep more heat in. Also, the weight of the soil squashed the barrel a bit, so the lid didn’t fit properly.