The researchers, from the EPFL in France, described in the awesome-as-it-sounds journal Nature Photonics how they did it. First, they chose "cold"— low intensity— laser to avoid frying the cells. The laser rotates its light around the sample cell, while a holographic camera captures images from every angle. Next, a computer crunches the images into 3-D. The process takes one image a minute, which sounds slow, but splice it together with other images over an hour, and you've got a 3-D movie. Another advantage is that the kind of contrast agents used in still photography, which can skew results, are not needed to capture the cells in action.