The prehistoric settlement at Poliochne lies in southwest Lemnos, about two kilometres from the present-day village of Kaminia in the wider area of Vroskopos, with the bay of the same name.

The settlement developed in the inner recess of Vroskopos Bay, upon a long and narrow gentle hillock running parallel to the coastline, in a general north-south direction. Its highest point, at 16.50 m asl, was formed mainly from deposits of human-generated debris, resulting from the multiple and successive phases of its continuous habitation. It is not possible to identify the initial limits of the east part of the settlement, due to erosion of the hill. Moreover, according to accepted models of sea-level change, the coastline at the time of the settlement’s existence was further east than it is today, since sea level is estimated to have been approximately 4 m lower during the fourth millennium BC, until it stabilized gradually at present levels.

The site offered an unimpeded view of the wider area, while the proximity of the fertile plain spreading to the north, west and south of the settlement, and the presence of water from nearby springs and two streams, which constituted its natural boundaries and embrace the hill, guaranteed not merely the survival but also the well-being of the prehistoric inhabitants. The privileged geographical position of Lemnos and indeed of Poliochne, 34 nautical miles from the Straits of the Hellespont (Dardanelles) and from the shores of Macedonia, played a decisive role in the development of Aegean culture, specifically with regard to the movement of peoples, the circulation of goods and, consequently, the diffusion of ideas, models and technical knowhow. This last is particularly apparent in the sector of metallurgy and metalworking, diagnostic elements of the period, as documented by the material culture remains. Metalworking at Poliochne is attested archaeologically from the earliest phases of the settlement and indeed with techniques, such as cire-perdue (lost-wax) casting, which are evidenced for the first time in the Aegean from as early as the third millennium BC, by the finding of a mould at the site.

The settlement at Poliochne covers 1 ha, even though its entire area has not been brought to light, and was inhabited without interruption from the mid-fourth millennium BC until the end of the third millennium BC. Isolated moveable finds indicate partial reuse of the site down to around 1200 BC.
The excavators used a colour code to designate the successive building phases of the settlement.

The Black period covers the founding and early years of the settlement, attributed to which are curvilinear walls that were the socles of huts with a superstructure of perishable materials, which were rebuilt immediately each time they were destroyed. The period is documented sporadically in deep excavation trenches and includes several successive building sub-phases, which correspond to alterations, repairs and/or rebuilding of the huts after a destruction. The dwellings were one-roomed and free-standing. Because these remains were found piecemeal and only where excavation proceeded to deep levels, little is known about the density, layout and other organizational features of the settlement in this phase, except that it appears to have been open and without an enclosure wall.
Blue symbolizes the next building phase at Poliochne, which corresponds culturally to the Early Bronze Age (henceforth EBA) period. Two main sub-phases are distinguished, the archaic and the advanced, with clear differentiation in the architecture and the pottery.
During the Archaic Blue period the settlement remained without an enclosure wall and was extended to the northwest and the southwest. Attributed to this building phase is a public benefit work and an early achievement of engineering, a well, which was later abandoned. A small stone-built conduit in the south sector of the settlement is another public work. The architectural remains attributed to this period are of houses. Although the full plan of a building of this period has not been revealed, the rectilinear walls, which in some cases are bedded directly on the curvilinear walls of the previous period, point to houses of quadrilateral plan. The walls are stone-built up to the roof and double-faced, with masonry of small stones and mud mortar made from the argillaceous soil at the site. The houses of this period seem to have been destroyed by a widespread fire. In the Advanced Blue phase innovations are encountered and proto-urban or urban characteristics: such as collective works that presuppose social, economic and political organization, central planning and collective execution, assignment of tasks and division of labour, control, technical knowhow and specialization in implementation. The private spaces present a tendency to standardization and repetition. Constructed on the basis of specific architectural models, they are incorporated in a perhaps single architectural programme for the radical design of the town, constituting the earliest instance of linear urban layout in the Aegean. Included among the public works is the enclosure wall built around the settlement, transforming it into one of closed type. This change affected also the general management of the available space and is a watershed of decisive significance for the urban development of the town. Other impressive technical works of public character are the retaining walls in the casemate technique, which served also other needs. Among these the large quadrilateral spaces reinforcing the slope, such as 14 and 28, which were at the same time part of the enclosure wall, but also 832. All are constructed in the emplecton system, as is the enclosure wall. These spaces have been identified as a bouleuterion, a granary and a megaron, respectively.
Attested in private architecture is the type of the megaron, which was elaborated and reached its peak in the ensuing periods. The plan of the settlement in the Blue period is difficult to decipher, due to the overlying constructions.
The Blue period was succeeded smoothly by the Green period (EBA Ι/ΙΙ), during which the population of the settlement is considered to have been at its highest, estimated at 1,500 persons. The settlement was expanded by constructing retaining walls forming manmade terraces on its previous margins. A propylon was arranged at the central (west) entrance to the settlement, with two square towers to protect it. Inside the settlement, without any drastic change in the construction technology of the buildings, building insulae were clearly formed, by the grid of streets. Indeed, the central thoroughfares and squares of the settlement are thought to have been laid out from at least this period if not earlier. Together with the contemporary settlement at Thermi on Lesbos, Poliochne is the earliest example of a settlement organized with building insulae, as lives on to this day, mutatis mutandis, in modern cities. Each insula included one building or several independent buildings with party walls. Each building has a courtyard, frequently shared with adjacent buildings, the residence proper (megaron) and ancillary spaces (for storage and for food preparation), in general alignment north-south. Between the buildings in each insula ran narrow side streets, facilitating circulation, while drains removed the rainwater from the roofs. The Green period is divided into two main successive building phases (Early and Late), outcome of a destruction that affected the entire settlement. Building remains of the Green period which confirm the overall plan of the settlement are visible today in the south and west sectors, while preserved backfilled are remains uncovered in excavations by the IASA under the overlying constructions.
The next two periods, Red (EBA ΙΙ/III) and Yellow (EBA ΙΙΙ) are represented architecturally by the remains visible on the crest of Poliochne hill. The enclosure wall was repaired and reinforced with additional bastions, the main streets were paved, the community buildings and the communal constructions continued to operate. No changes are observed in the urban plan but differentiation is identified in the construction technology and the orientation of the buildings. Specifically during the Yellow period, when the city was rebuilt after a conflagration, possibly due to an earthquake, the masonry is less careful with the use of irregular fieldstones and abundant mud mortar. The architectural forms are standardized and the enlargement of the private buildings takes place at the expense of public space, indicating a trend for introversion or simply lack of space in relation to the preceding periods. Basic unit of each building is still the megaron, a single space of oblong plan with entrance on one narrow side, usually the south, on the same side an open antechamber accessed directly from a paved court, and sometimes and opisthodomus. The megaron is flanked by other ancillary spaces, sometimes roofed and sometimes open. The end of the Yellow phase and the abandonment of the settlement at Poliochne was brought about by a catastrophic earthquake ca 2000 BC, after which it never recovered the extent or the intensity of previous years.
The construction of an enclosure wall that transformed the settlement from an open to a closed type, roughly speaking from a village of free-standing huts to a town with complex houses in demarcated zones, is a turning point with multiple connotations, at least semiologically. First of all, the need to delimit the living space is predicated on the mutual acceptance by the members of the community that they make up a body that is different from other communities outside this enceinte. This implies the poetic of a collective identity that separates the people living intra muros from those extra muros. In other words, the enclosure wall circumscribes the limit of action of a specific community. Furthermore, its construction defines a rectilinear area and it is perhaps not fortuitous that the overwhelming majority of the buildings it circumvallates are likewise rectilinear in form. From the point in time when the enclosure wall limits the field of development of the settlement, those who use the space are obliged and/or are ready to resort to more rational solutions for managing the space, inevitable outcome of which are the urban plan or even spatial organization of the settlement. Inevitable too is the introversion of the community, when the prevailing circumstances (social, demographic, economic, and so on) impose this.
Whatever the case, the conception underlying the construction of the enclosure wall, whether this functioned as a retaining wall or a fortification or a marker of property ownership, or some or even all of these functions, and the consequent choices of management of space bear witness to advanced social structure and cohesion of the community. This was the outcome of specialization, intensification of production and therefore the possibility of storing the agricultural surplus, and in the end the more general economic prosperity.
The settlement at Poliochne was in the vanguard of developments in all these sectors and its uniqueness among all the other known prehistoric settlements in Europe, at the time of its discovery, gave it the sobriquet the earliest city in Europe. Today, almost a century after the first excavation at Poliochne, the archaeological archive has been enriched by investigation of settlements of similar character: some earlier, contemporary or later, some larger or smaller, some of greater longevity others short-lived, some more fragmentary, others allusive. However, the earliness, the importance and the influence of the achievements of the settlement at Poliochne within its geographical and cultural context is incontestable.