“Market St. San Francisco -- 1906. Street scene of Market Street in San Francisco before the earthquake and fire of April 1906.” “Old City Hall S.F."c. 1906.

A screengrab from restored footage of Market Street in San Francisco on April 14, 1906, four days before the earthquake.

A rare set of 20 fading sepia photographs, taken in the days following the earthquake and fire that changed San Francisco forever, are being auctioned this week.