It is connected with the watermills of Almopia (such as the traditional watermills in the area Voreino - Neochori - Pefkoto), the thermal baths, the waterfalls of Almopia, the Bridge of Aloros and other places of historical interest related to the water element, and it is fair to highlight the architectural significance.
The role of water in Almopia
The river, Moglenitsas or Upper Loudias was literally a source of life for the residents of Almopia both in the past and in modern times, as the economy of the region remains predominantly rural. The area is characterized geographically from the fertile plains of Aridea and the surrounding mountain peaks of Vora, Tzena and Paiko. This plain area, is a place with high-value agricultural ecosystems. This is due to the low relief of the land and the presence of water (which is offered with plenty from the river Moglenitsas and its tributaries).
The water, the mills and the culture of cereal
The local economy is based mainly today on rural culture. There are produced, many and varied products, especially vegetables. Cereals are not grown on a large scale, in contrast with the past, whose production appeared to be extensive and prosperous. This substantiates the presence of two water mills, that survive today in Sossandra. Watermills, especially those for grinding grain, are artisanal economy reference point not only in the Greek area but also in the wider Mediterranean throughout the course of Byzantine and post-Byzantine period. Most mills that survive nowadays, date from the second half of the 19th to the second half of the 20th century.
Although the water wheel is very old invention, as mentioned in inscriptions of the Sumerian, the watermill is marked first by the name '' ydraletis '' by Stravona (1st century BC-1st century AD). Its invention was revolutionary, and allowed the grinding of large quantities of grain, which until then was exclusively manually. Quickly it was spread to the known world. In Greece was widely used, mainly for flour production, although it was also used for grinding special materials useful in tanneries, gunpowder and mortar (masonry). In Greece, functioned two basic types: the oldest “Roman” with the upright external winged, and especially the younger “Eastern or Greek-type” with horizontal internal. In mainland Greece and on the large islands were built thousands of such small craft facilities. They were usually family businesses and even when the mill was located near the village, here was the home of the miller.
The watermills had usually a couple of millstones, and then called one-eyed. Rarely, when there was a lot of water, they had two and were called binocular. They were often organized in clusters along the ravine so that the exploitation of the water is sequentially. These are simple structures, tailored to the local architecture. A simple rectangular room, had in one side the grinding mechanism and on the other side was the point where customers were waiting. Under the millstones was the kinetic mechanism (the water wheel, the impeller), where it led the bellows of the cask (the wooden or later metallic water pipeline), or water tower, from where the water was splashing on the blades of the waterwheel. In this way, the water rotated the waterwheel. This movement was transmitted to the millstones with a vertical axis, which were used to grind the fruit that fell on them.
Apart from the mill, infrastructure projects were equally important for both the transport of water (wells, waterways, ditches, bridges, etc.) (especially when the water had to be transported from afar) and that of the cereal initially and the flour later to the construction of cobblestone. There were extremely important facilities for the local economy, so in many cases we meet some fortifications.
The Water and the Bridges
In Almopia plain (which is surrounded by high mountains), the only “way” to the south is the narrow region of Apsalo-Moglenitsas (region characterized by river valleys) and the hilly area that offers easy pass. The gullies were (already from prehistoric times) accessible places and passages, communication roads and migration roads.
The settlements were established primarily near water. Many times, the crossing from one side to the other of a torrential river, it was difficult or dangerous. The construction of bridges was therefore necessary in traditional societies of preindustrial era. Through them, people and goods were moved (mainly between settlements). Thus, their construction has been an integral and important part of a road, which was vital for the residential development of a place and now in most cases no longer used. They are, however, characteristics and remarkable examples of local architecture.
The stone '' Bridge of Alexander the Great '' (Bridge in Aloro) is located on the southern edge of the plain of Almopia, on the river Moglenitsa, near the village Aloros. Today it is outside of the main street of the area (Pozar-Skydra) and in a position that is inaccessible, as there is no longer communication from the crossing, forming from Moglenitsa. The bridge formerly connected the villages Aloros and Xifiani with the opposite villages : Golden, Krania and Theodoraki at the foot of Mount Paiko.
Unfortunately, there is no written information about the builders of Macedonian bridges. The most, however, were built by Macedonians artisans of the building art, coming from the so-called 'Mastorochoria' of Western Macedonia. The Macedonians masters along with people from Epirus, considered to be the top of their kind in the Greek area.
The architecture of the stone bridges of Macedonia
The architecture and construction technique of Macedonian stone bridges, is no different from that of Continental or the rest of Greece. A key component of a bridge is the arc, which in most cases is semicircular up to elliptic and very rarely pointed. Many of the bridges were multi-bows, as the construction of arches, with large windows and to a large amount had largely manufacturing difficulty.
The choice of location was the first important step in the commencement of work, which was emphasized not only from the course of the road that connected, but also by the type of soil of the river (the rock was preferred as it was fixed) and by the smaller width of the riverbed. In some cases, it was taken into account the smaller depth of the river.
The construction of the piers, foundations ie, was naturally first. Usually, it was of rectangular section (the bridge of Alexander the Great in Almopia is hexagonal) and stones were hewn. Then, there were manufactured bows using wooden molds. The piers were built simultaneously on both sides, from bottom to the top. The stone arches were carved in trapezium-shaped, so that to be wedged together. The last stone of the arch that were placed on top, called "key". By removing the wooden frame, the entire structure was shifted a few centimeters down and thereby acquired a coherent structure and a stability. The type of masonry, that used by the masters of the bridges, were varied. Usually, it was plaster or mortar or a variation of these species.
Common feature was the rectangular openings with arched lintels, which eased the whole construction (relievers), while operating as 'overflows', where the water level rose dangerously. Also, on the pedestals manufactured triangular projections so as to direct the water to the arches and to avoid (as possible) the lateral pressure from the flow of water. Finally, the roadway of the bridge was covered with stone pavement (cobbled road), while often constructed parapet.
Although in general, all these describe how they constructed a stone arched bridge, it should be noted that each of the bridges was distinguished for its particular characteristics, eg different materials, different masonry etc. These differences are usually due to different periods of time in which the bridges were constructed.
As regards, finally, the creators of Macedonian bridges, the builders ie and sponsors, unfortunately have not been saved data. Most bridges, were built by masons who came from western Macedonia, especially from the province Voio prefecture of Kozani. About the sponsors, usually were local notables, priests, landowners or wealthy expatriates. It was indeed ordinary, the bridge to take the name of the sponsor, (this habit over the years, disappeared).
 M. Axiotis (1999), The streets of water. The water mills as cultural monuments in Lesvos, Lesvos, p. 10.
 Chr. Agriantoni (2009), Open-air Water Power Museum, Guide, Athens, p. 14.
 St.. Nomikos (1997) The Water Power in preindustrial Greece, Athens, p. 23.
 Ibid, Ch. Agriantoni (2009), Open-air Water Power Museum, Guide, Athens, pp. 18.
 St.. Nomikos (1997) The Water Power in preindustrial Greece, Athens, p. 27.
 M. Axiotis (1999), The streets of water. The water mills as cultural monuments in Lesvos, Lesvos, p. 4-9.
 G.P Tsotsos (1997) Macedonian bridges. Topography, architecture, history, folklore, Thessaloniki, pp. 117.
 Ibid, p. 26-27.
 The data tha are presented, come from the book: G.P. Tsotsos, Macedonian bridges. Topography, architecture, history, folklore, Thessaloniki 1997, pp. 21-28, 115 and 117-118.