What is a bastion system?

A bastion is an element of the defence construction which developed parallel with the artillery. Originally, it was developed in Italy in the 15th and 16th centuries and later it was accepted within and even outside Europe, right up until the 19th century. It is of a pentagonal layout, of the same height as the surrounding ramparts, and is intended for the artillery. During an attack, the bastion did not have the so called dead angles (blind spots), that is, points against which the defenders could not direct their fire.