The Guardian interviews Renzo Piano, the world's most famous Italian architect, and he shares his sandcastle-building tips. He argues that it is not necessary to be a child to create sandcastles; all that is required is the ability to think like a child. "First and foremost, it must be understood that building a sandcastle is a momentary operation. You shouldn't have too high expectations because the castle will only endure a short time before being eaten up by the waves. As a result, it should not be put too close to the water, nor too far away: the interaction with the waves and the analysis of their movements is one of the most interesting aspects of the process. It sounds more complicated than it is, but it is actually simple and instinctive". Second tip: "Draw a ditch with your hands where the waves have left moist sand. The ditch should not be deeper than roughly 30 cm. Gather the sand into the shape of a miniature mountain about 60 cm high, with the sides sloping at a 45-degree angle". Third: “Dig a channel that allows the waves to enter". "The last touch is to add a little flag or something else on top of the castle. This will make it more noticeable to those running along the shore. Then head home without looking back".