Early historical records bear witness to the occurrence of great sunspots in past centuries, and telescopic records have contributed more precisely to the story which is taken up by the Greenwich observations started in 1874. Since then, fifty-four great spots, with a mean area for the solar disk-passage of ⩾ 1500 millionths of the Sun's hemisphere have been observed. These spots, of which the first appeared in 1882, are listed in an Appendix. Their characteristics are briefly considered, including a marked tendency for them to be associated with geomagnetic storms. The progress of the observational side of solar physics during the past seventy years is then reviewed against the background of these great sunspots which, by virtue of their size and range of associated phenomena, have presented themselves as unique objects for observational research.