Each crystal is made out of a salt solution that grows around a LED. Wirelessly charged via a special power mat, the crystals come alive at night when visitors start adding, moving or sharing them. Crystal is the Lego from Mars, says Dutch artist Daan Roosegaarde. He’s referring to its ‘spacey’ design and share-ability. ‘Crystal allows people to express their stories in a very public way. You can either share or steal them’, says the Dutch artist. ‘I see both actions as a compliment’.