Bilsk is really three fortified settlements, Kuzemyn, Western Bilsk, and Eastern Bilsk, bound together by the immense enclosing wall known as the Great Bilsk hillfort. The two primary strongholds went up in the seventh and sixth centuries BC, one above the Sukha Hrun and one above the Vorskla, and the Kuzemyn fortification followed in the fifth. Each was defended by deep ditches and tall ramparts topped with wooden walls and towers. The Great fortification's defenses alone stretch nearly twenty-six kilometers. Beneath it all lie even older traces, Bronze Age layers of the Srubnaya and Bondarikha cultures, so that the site records not one moment but the deep sediment of human presence on the edge of the steppe.

The community that filled Bilsk was not a single tribe but a mingling of peoples, the Budini, the Gelonians, the Neuri, and probably others, living together within the ramparts. Excavations have uncovered the texture of their daily life: sunken and above-ground dwellings, cellars and granary pits, and the workshops of blacksmiths, bronze founders, jewelers, potters, and bone carvers. There are altars and temples, one perhaps used for astronomical observation, and scatterings of ceramic figurines, human, animal, and bird-shaped, along with objects that hint at fertility cults tied to the fields. On the eastern settlement, archaeologists even found signs of planned farmsteads and two-story wooden buildings, a real town rather than a rough camp.

What made Bilsk thrive was its position and its reach. Sitting where the open steppe meets the forest-steppe, it commanded an extensive web of river and land routes. Boats set out from a pier near Kuzemyn down the Vorskla to the Dnieper and on to the Greek colony of Olbia on the Black Sea coast; overland tracks led to the Muravsky Trail running south toward the Greek cities of the Crimea. Along these arteries flowed trade on a large scale, and the goods left behind prove it: imported painted dishes, amphorae, and glassware from many centers of the classical Mediterranean world. A settlement deep in the Ukrainian interior was woven, through commerce, into the life of ancient Greece.

Around the third century BC, the world that sustained Bilsk began to unravel. Shifts in climate disrupted the trade and farming the settlement depended on, croplands grew less productive, and life gradually ebbed away until the great center was no longer great. Smaller communities came and went across the centuries, and in the early seventeenth century Cossacks and settlers worked the ground for saltpeter, damaging the ancient ramparts in the process. Serious archaeology began in 1906 with Vasily Gorodtsov, and since 1954 the site has been studied systematically, notably by Boris Shramko and later a joint Ukrainian-German expedition, with excavations continuing today under Iryna Shramko. Slowly, the darkness of antiquity that once baffled early observers is giving up its secrets.