One of the most ambiguous research and technological projects started 2005 in Cadarach France. Leading nations joined forces to built a demonstration reactor to artificial produce energy on earth mimicking the fusion process in the core of the sun. Since then complex components, designed and manufactured all over the world are transported to the construction side, inspected stored or directly installed. This includes single parts of 6 by 9 by 5 m and 900 t as well as delicate optical diagnostic systems. On one hand side consider a big building construction side with the target to operate in ISO3 conditions at the end. To align these along the different phases is target of an ITER, OHB application and expert team. Within the talk the Iter concept, some technical challenges, the link to cleanliness engineering and solution concepts will be briefly addressed. A 200 to one model will be presented to visualize the size and trigger further discussions on this outstanding future technology.