This paper reviews the design, engineering principles and applications of machine tools specially developed for large parts. Large workshop machines are commonly used for manufacturing, where the impact of the general engineering principles differs substantially from those applied to conventional size machines. Portable machines are used during assembly and operation due to mobility, agility and energy constraints. Such large dimensions produce an amplification factor of any error source, so verification and calibration of such large or portable machines becomes even more critical than in conventional machines. The paper also includes future trends and unsolved challenges.