If you thought you knew what geometry is all about, then this issue of

*Plus*may change your mind. We explore a strange point-less geometry of spacetime, find out about hyperbolic geometry's amazing fractals, celebrate a geometric formula named after Leonhard Euler, the most prolific mathematician of all time, and try to calculate pi. This issue also contains the first ever*Plus*teacher package and, to celebrate our tenth birthday, continues our series on the history of*Plus*.June 2007