It is the most crucial mechanism in life – the division of cells. For 25 years, it has been known that bacteria split into two by forming a Z ring at their centre. They use this to cut themselves into two daughter cells. Using advanced microscopes, researchers from the universities of Harvard, Indiana, Newcastle, and Delft have succeeded in finding out how bacteria do this. The bacteria appear to build a new cell wall working from the outside in with the help of multiple molecular ‘bricklayers’, in about a quarter of an hour. What was completely unexpected was that the ‘bricklayers’ move along the inside of the wall under construction by ‘treadmilling’; the building of the cell wall is performed from scaffolding that is continuously being moved at the front, while at the rear it is continuously being dismantled.