Blockchain technologies are in great demand from many companies around the world. However, almost a decade after the establishment of Bitcoin, there is a great deal of confusion regarding what they are, how they are to be used, and what the risks are related to these rapidly evolving systems. This presentation elaborates on the definitions, history, and security issues surrounding blockchains and their applications. This includes an introduction to blockchains and their key terminology which will be followed by an examination of notable projects in the blockchain space and hacks these projects have experienced. We will conclude with the potential futures of these technologies and current challenges affecting those futures.