Downtown Sioux Falls is a rich environment for buildings made of Sioux Quartzite. For information about Sioux Quartzite, follow this link here, and this one here.
Old Courthouse Museum.
Saint Joseph Cathedral.
Not everything I photographed is related to Sioux Quartzite, for instance, this is the Statue of David in Downtown Sioux Falls, and is one of only a few actual size replicas of the original. The statue did not come to the city without controversy .
The Minnehaha County Courthouse.
We checked the time on this sundial, and it was right on the money.