Why are fortresses often pentagons




















Fort cannons can be easily moved from one wall to the next, and out on the arrow-shaped redans. From there, up to three such redans can fire upon enemy forces at long ranges, or two redans from shorter ranges. The trace italienne , by contrast, can only fire on an enemy from two redans. It gets worse. If an army attempts to storm a Vauban fort, the defenders can engage them from multiple directions.

Not only must an attacking army face fire from the front, but the pentagon shape also means defenders can take them under fire from their flanks. If an attacker tries to attack a redan head-on, up to three of the redans can take them under fire at once. Some forts included moats, constructed at a distance, that mirrored the shape of the forts. The moat wasn't meant to be impregnable, but rather to slow down an attacker and give the defender time to prepare.

Enemy forces would also bunch up near moat crossings, making excellent targets. Today, more than years later, the Vauban forts are back in style. Malinese insurgents aren't a sophisticated, well-trained enemy, and the most the French might expect is a mass attack by ill-trained guerrilla forces across open ground.

The Vauban fort of the 21st century retains all the advantages of forts constructed in the 17th century, and one fort in Mali even has a star-shaped ditch that mimics a moat in purpose. But fort patterns from the 16th century can only go so far in the modern era. Vauban forts would be disastrous against a modern, mechanized enemy such as the Russian Army. A modern adversary would pound the fort to pieces with air strikes and artillery, while tanks and other mechanized would simply bypass the fort.

First constructed in , Fort Independence was constructed in granite on Castle Island in a star shape full of cannons to protect the mainland. While multiple rebuilds reshaped the fort over the years, the allure of Fort Independence remains today.

It is the oldest continually fortified site by the English in the United States. Built on a rock island in the Arabian Sea near the coastal village of Murud, Fort Murud-Janjira is reachable only via the sea. With 21 bastions, the Indian fort was originally built in the 15th century, but enlarged over time. The main gate remains hidden until those approaching the fort come within less than 50 feet of the island.

Another gate stands on the opposite side of the island. One of the largest underground structures in Europe, the Zeljava Airbase is tucked underground along the border between Croatia and Bosnia-Herzegovina. While monitoring airspace in Europe and offering an early warning system, the facility also served as a potential respite for nuclear attack. The Yugoslav wars ravaged the site, though, and it was booby-trapped with land mines to prevent its potential future use. Scheduled for delivery to the U.

Navy in , the Gerald R. Ford -class aircraft carrier will replace both the Enterprise and Nimitz -class carriers with its ability to operate with nearly fewer crew. Technology upgrades include the first all-electric utilities on a carrier, eliminating steam service lines, a new reactor style, an updated aircraft launch system, fresh radar, and more. The Gerald R. Ford class will get planes into the air faster, run more efficiently, and strike more quickly.

These fortified towers poking up in the Thames and Mersey estuaries were built to protect England from German submarines. The forts also watched for submarines and housed antiaircraft guns used throughout World War II.

The small towers, grouped in six forts, were decommissioned in the s but many still remain, today rising above the water level with rusted power and impressive intrigue. Type keyword s to search. Today's Top Stories. Why the U. Could Best China in the Indo-Pacific. The 9 Best Robotics Kits for Kids. Chris Caldicott Getty Images. Crac des Chevaliers, Syria. Historical Getty Images. Edwards Air Force Base, California. Giles Clarke Getty Images. Fortress of Suomenlinna, Finland.

Fortress of the Orsini, Italy. Yann Arthus-Bertrand Getty Images. Masada, Isreal. Mukachevo Castle, Ukraine. Wikimedia Commons. Google Maps. Raven Rock Mountain Complex, Pennsylvania. Mario Tama Getty Images. Thule Air Base, Greenland. John James Wood Getty Images.

Gibraltar, British Oversees Territory. George Steinmetz. Cheyenne Mountain Complex, Colorado. Claude Renault Getty Images. Chittorgarh Fort, India. Ramiro Olaciregui Getty Images. Windsor Castle, U. Jim Edds Getty Images. Fort Jefferson, Florida Keys. Dado Daniela Getty Images.

Prague Castle, Czech Republic. B Flying Fortress, U. Christian Kober Getty Images. Malbork Castle, Poland. Stocktrek Images Getty Images. USS Nimitz, U. An outstanding example of symmetrical pentagon design is the restored Fortress of Bourtange in the eastern Netherlands.

A visitor can walk around the inside and outside the restored fortress, which has tourist accommodations and a museum.

The Shape of a Fort For the best angles to shoot along each bastion face as well as the walls, the most practical overall shape to the new artillery fort became a pentagon, with sturdy bastions protruding from each corner of the pentagon.

Favored were: Central point with streets radiating out, as shown in the illustration. A grid pattern, which offered a bit more space for buildings, but perhaps movement was not quite as fast as could be had with radiating streets in 1. As efficient as the pentagon design was, it could be too much for a scaled-down fortification, in which case four bastions were made or even three.



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