The Dannebrog, the Danish flag, being lowered at the Governor's Mansion for the last time on this date in 1917. Note the fence made of chain and cannon.
On this day in 1917 possession of the Danish West Indies from Denmark to the United States was accomplished, although it appears the official start of US ownership of the islands was the following day, April 1. The treaty and other events leading to this were addressed earlier on this blog.
The day is commemorated on the US Virgin Islands as Transfer Day.