Octagon houses were a unique house style briefly popular in the 1850s in the United States and Canada. They are characterised by an octagonal (eight-sided) plan, and often feature a flat roof and a veranda all round. Their unusual shape and appearance, quite different from the ornate pitched-roof houses typical of the period, can generally be traced to the influence of one man, amateur architect and lifestyle pundit Orson Squire Fowler. Although there are other octagonal houses worldwide, the term octagon house usually refers specifically to octagonal houses built in North America during this period, and up to the early 1900s.