Generate a photorealistic image of a medieval castle, with towering walls and majestic towers, standing tall and proud against a backdrop of rolling hills and a clear blue sky. The castle should exude an aura of power and grandeur, reminiscent of the formidable strongholds of the Middle Ages. The castle should be made of stone, with a weathered and timeworn appearance. The walls should be thick and imposing, with crenellations along the top. The towers should be tall and slender, with pointed roofs. The castle should be surrounded by a moat, with a drawbridge leading to the main gate. The overall impression should be one of strength, majesty, and invincibility.