The coffin includes a moss bed, plant roots, and a number of living microorganisms with a wood-chip and mycelium serving as the materials for the coffin’s exterior walls. Usually, it takes up to 12 years for the body to fully decompose depending on various conditions. Besides whatever junk we ate that got stuck in our bodies, things like varnished and metal coffin parts as well as synthetic clothing can stay underground for much longer periods of time.