99 years ago this week, the biggest solar storm of the 20th century struck Earth. It set fire to buildings, burnt out telephone lines, and sparked auroras as far south as Tonga and Samoa. New research suggests that the Great Geomagnetic Storm of May 1921 may have been even stronger than previously thought.
https://spaceweatherarchive.com/2020/05/12/the-great-geomagnetic-storm-of-may-1921/