 Megaprojects refer not only to construction projects but also decommissioning projects, which are projects that can reach multi-billion budgets, and have a high level of innovation and complexity, and are affected by a number of techno-socio-economic and organizational challenges.Megaprojects include bridges, tunnels, highways, railways, airports, seaports, power plants, dams, wastewater projects, Special Economic Zones, oil and natural gas extraction projects, public buildings, information technology systems, aerospace projects, weapons systems, large-scale sporting events and, more recently, mixed use waterfront redevelopments; however, the most common megaprojects are in the categories of hydroelectric facilities, nuclear power plants, and large public transportation projects.Megaprojects can also include large-scale high-cost initiatives in scientific research and infrastructure, such as the sequencing of the human genome, a significant global advance in genetics and biotechnology.