Credit: M. LAK, P. TAFFOREAU, D NÉRAUDEAU

Suspended deep inside opaque pieces of amber, this spider and conifer branch have remained hidden for around 100 million years.

Now they, and some 350 other organisms including wasps, flies and ants, can be viewed thanks to a technique that can see through the fossilized tree resin that holds them.

French palaeontologists at the University of Rennes, in collaboration with the European Synchrotron Radiation Facility in Grenoble, used a synchrotron X-ray imaging technique called propagation-phase contrast microradiography to make the organisms visible. They examined around two kilograms of opaque amber from mid-Cretaceous sites in southwestern France and produced a series of spectacular three-dimensional images (see http://www.esrf.eu/news/general/amber).