Create a highly detailed, ultra-realistic 3D model of an ancient stone fortress with multiple levels, arched doorways, and staircases. The structure features a tiered design with rough, granular texture, small windows, and a rocky base that blends into the landscape. Ensure 4K resolution to capture fine details and textures. Use balanced lighting to highlight the intricate features without harsh shadows. The background should be neutral to keep the focus on the structure.