The Torre del Fraile is one of a set of military watchtowers built around the South and East coast of Spain to keep an eye on passing shipping and Barbary pirates. The watchtowers were in sight of one another and it was therefore possible to get a signal to Gibraltar from the watchtower in Tarifa. The tower was designed by Luis Bravo and Juan Pedro Laguna in 1588.
The tower is about 240 metres back from the sea and Cala Arenas and 120 metres above it. The tower is over six metres in diameter and was over thirteen metres high until the top collapsed in 2006 with the loss of a window and the upper staircase. The tower's entrance was over five metres in the air and this led onto a floor. From this the soldiers could climb to the top where space was reserved for firewood for signalling.References:
Goryōkaku (五稜郭) (literally, 'five-point fort') is a star fort in the Japanese city of Hakodate on the island of Hokkaido. The fortress was completed in 1866. It was the main fortress of the short-lived Republic of Ezo.
Goryōkaku was designed in 1855 by Takeda Ayasaburō and Jules Brunet. Their plans was based on the work of the French architect Vauban. The fortress was completed in 1866, two years before the collapse of the Tokugawa Shogunate. It is shaped like a five-pointed star. This allowed for greater numbers of gun emplacements on its walls than a traditional Japanese fortress, and reduced the number of blind spots where a cannon could not fire.
The fort was built by the Tokugawa shogunate to protect the Tsugaru Strait against a possible invasion by the Meiji government.
Goryōkaku is famous as the site of the last battle of the Boshin War.