According to Janssens' this is the 12th largest sunspot group since records began in 1874! He's got the data to prove it. It is a bafflingly complex group - note the inversion line between opposite polarities (blue line) -(c) SDO Satellite. Why did it grow so big? Back in Sept. 2014 it probably began as AR12172 - but late in that month the already large group was joined by myriad small new spots covering a wide area, Shaken and stirred during its far-side transit - and THIS is what returned: AR12192! An amazing group. It will return to the east limb about November 12th. Stay posted!