I am writing the first book from the American point of view about 19th century rotunda panoramas. These were the biggest paintings in the world, 50 x 400=20,000 square feet, housed in their own rotundas which were 16-sided polygons. Chicago in 1893 had 6 panorama companies and 6 panorama rotundas. See my AskART discussion board on William de Leftwich Dodge. I have much info to share.