Computer technology has become highly complex, widely available and thanks to growth and popularity of the Internet, society and organisations are becoming heavily reliant on distinct computer technology to meet objectives and fulfil daily demands. Unfortunately distinct systems cannot always fulfil the complex requirements demanded; hence distinct systems are now being integrated to form larger collaborating systems to meet intended requirements. These systems are defined as "Systems-of-Systems", and are emerging in areas such as critical infrastructure, space exploration, and the military. This paper highlights some of the challenges faced when integrating distinct systems to form these large complex heterogeneous Systems-of-Systems, we identify Systems-of-Systems that have failed and the disastrous consequences. Our research also discusses how single points of failure can heavily impact collaborating systems abilities to fulfil objectives, which can result in them failing with disastrous consequences.