For over half a century, biologists have been culturing cells in vitro, or in a dish, separate from the organisms they come from. Many of the natural features of a cell can be recapitulated in culture; however, our inability to specifically recreate their native environment is a significant hurdle in understanding countless cellular processes and associated diseases. Within an organism, cells take cues from surrounding tissues and cells, and from the kind of surface on which they exist. Such signals instruct the cells when they should divide, or differentiate into a new cell type, when they should move, and even when they should die. Creating a setting that is as close as possible to the natural environment of a cell is essential for truly understanding how cells work.