The first animals came onto land sometime before 425 Ma. These early colonizers were members of a group called the arthropods - probably early relatives of the millipedes first. However, early land animals - especially those from the Palaeozoic era (542 - 252 Ma) - are relatively rarely preserved as fossils. The Carboniferous period (350-299 Ma) is an exception to this rule. During the Late Carboniferous, there is a window in which land animals are found preserved within the iron carbonate mineral siderite. This kind of preservation allows palaeontologists to use 3D reconstruction techniques - such as high resolution CT scanning - to investigate this unique insight into early land-based ecosystems. We talk to Dr. Russell Garwood - an 1851 research fellow at the University of Manchester - about the Carboniferous, the land animals which were around at the time, and the techniques he uses to study these.