Around 1,300 Leideners found 2,265 species during the Expeditie Stadsnutuur urban biodiversity inventory. ‘It’s been a huge success’, says scientific coordinator Frederic Lens.

After months of preparation, the moment of truth had arrived: would the skies above Leiden clear for the promised glitzy planet-and-star show? The people of Leiden turned out in their hundreds to go star-hunting on 25 September. They became more aware than ever of the effects of light pollution.