Collier's New Encyclopedia (1921)/Fortress

FORTRESS, the development of modern ordnance has rendered fortification as exhibited in the construction of the fortresses of the past practically obsolete and useless. It is probable that no fortress in the world (with the exception, perhaps, of Gibraltar) would form a serious obstacle to a modern naval or land attack, if the assailants were provided with the most approved modern heavy guns. In view of this fact, the construction of fortresses has been directed almost entirely to enabling them to cause a ricochet of shots directed against them rather than to oppose the direct impact. Hence modern fortresses are usually small, and present nowhere a direct angle to the line of fire, being generally constructed on the turtle-back or spherical plan. They usually contain but few guns, and those of the heavier calibers, rendering them offensive, rather than great strongholds of defense, as formerly. Of this latter class the strongest fortress surviving in the United States is Fortress Monroe, on Hampton Roads in Virginia, erected for the defense of Norfolk navy yard and the Virginian coast at that point. It was planned and built by a French engineer, and was an important Federal stronghold during the Civil War. Other important historical fortresses are McHenry, Moultrie, Pickens, Webster, St. Augustine, and Sumter.

The greatest fortress in the world, from a strategical point of view, is the stronghold of Gibraltar, on the coast of Spain. It occupies a rocky peninsula jutting out into the sea, about one and a half miles in length and three-quarters of a mile in width. One central rock rises to a height of 1,435 feet above the sea level. Its N. face is almost perpendicular, while its E. side is full of tremendous precipices. On the S. it terminates in what is called Europa Point. The W. side is less steep than the E., and between its base and the sea is the narrow, almost level, span on which the town of Gibraltar is built. The fortress is considered impregrnable to military assault. The regular garrison in time of peace numbers about 7,000. It belongs to England.