The star fort of Bourtange

This magnificent landscaping project, located in the Netherlands, is in fact a sixteenth-century military fortification called a star fort. These were quite popular throughout Europe at the time, although they proved to be less effective than other arrangements and quickly fell out of favor. There is even a star fort in Japan, constructed during the Tokugawa shogunate (mid nineteenth century).  Star forts are a particular interest of Deputy Dog, who has more info and photos at the link.