In the field of nuclear fusion some are going big with their pursuit of clean, inexhaustible energy, like those piecing together the seven-story building to house ITER, the world's largest tokamak reactor. 

The development of the novel magnet was led by MIT scientists working on an experimental fusion reactor design first revealed back in 2015. Called ARC (affordable, robust, compact), the reactor is a doughnut-shaped tokamak, which like ITER seeks to recreate the conditions inside our Sun that sees hydrogen atoms fuse together under extreme heat and pressure to release massive amounts of clean energy. ARC, however, will be around half the size of ITER, with a radius of 3.3 m (10.8 ft).