The longest glow-in-the-dark (chemiluminescent) necklace measured 326.44 m (1,071 ft) and was created by Dr Bunhead's alter ego, Tom Pringle, with the help of Helen Maynard-Casely and The Glow Company (all UK) as part of the Edinburgh International Science Festival at Dr Bunhead's Pyromania show, in Edinburgh, Scotland, UK, on 9 April 2011. Chemiluminescence occurs when the solid esther diphenyl oxalate (Cv14Hv10Ov4, trademark name Cyalume) reacts with hydrogen peroxide, producing photons of light. The two chemicals are isolated inside plastic tubing, and when the tube is snapped, the fragile divider between the two breaks, allowing the chemicals to react together. To achieve a range of colours, chemical dyes can be added: e.g., 9,10-Diphenylanthracene for blue, Rhodamine B for red. The longest glow-in-the-dark necklace was worn around the necks of 100 children, simultaneously.