Challenges could be observed as opportunities for success. The growth of project management body of knowledge and the advancement of project managers' capabilities in dealing with resources are crucial to the successful delivery of projects. As the main objective of this paper is to overview the key challenges for project managers in the current century to help the Future Built Environment, a systematic literature review analysis on PM features was conducted by evaluating over 256 published research papers under the Project Management topic during the past 15 years (2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015)(2016)(2017)(2018). As result of this exploration, the research highlighted 18 main challenges and over 125 parameters related to challenges in projects from the extant literature. The management of uncertainty and dealing with different challenges are necessary conditions for effective project management. Sources of challenges are wide ranging and have fundamental effects on projects and the project management body of knowledge. These challenges are not limited to specific industries, and include scope management, information technology, team dynamics, customers' satisfaction, lean management, communication, innovation and quality. Common project management body of knowledge does not address many of the listed sources of challenges, particularly in 'soft' project management skills where flexibility and tolerance of PMs are necessary. The findings of this review paper help scholars to put their attempts on key challenges in managing projects effectively. Such attempts need to entail project managers' capabilities as well as the organization maturities including some aspects of organisation culture and learning.