Over a thousand years ago, builders designed an immense vessel that has spanned centuries, still and solid, at the pace of the earth in the universe. Knowing this is entering an arch where the sky and the earth resonate with the self. This arch takes on special colours in the four key moments in the cycle of seasons, when days start getting longer or shorter, when the earth warms up and flowers appear, or when it protects itself against the cold. On the very day and at the exact time of a solstice or an equinox, the builders' secret will reveal itself - the wheel of time, the power of the seasons, the present that lights up the past and makes the future possible, the moment that comes and goes, brushing with eternity. With a postface by Charles Bonnet.