November 21: Devils Tower & Spearfish Canyon . . .
Read MoreThe Homestake Mining Company was a large gold mining operation that existed from 1879 through 2001 when it was merged into the Barrick Gold Corp. of Canada. It's known for being the second largest gold producer and for being the longest continually operating mine in the US. Two hydroelectric power plants were built specifically to supply power to the mines - Plant #1 in 1910 and Plant #2 seen above in 1917.