This close-up from a video clip taken May 30-June 1, 2018 shows a large active region in extreme ultraviolet light as the bright magnetic field lines above it shift and twist. Note the Earth scale below the active region: the longest loops extend about 10 times the diameter of Earth. When the magnetic field lines get themselves tangled up enough, they can erupt with a solar storm.
Videos are available at https://photojournal.jpl.nasa.gov/catalog/PIA22475