concept art of city 1 7, from the half - life universe, civil protection, cameras, drones, combine mechanical technological weapons to control. at the heart of the city is the citadel, a giant skyscraper which serves as the hub of the combine. hyperrealist, intricate digital art, breathtaking, artgem, artstation, volumetric lighting, real time render, 8 k ultra high definition, unreal 5