Create a mesmerizing collection of ultra-detailed watercolor clipart, combining the enchanting beauty of autumn with the bustling charm of the city. The clipart should feature vibrant autumn elements, such as colorful leaves, pumpkins, and acorns, seamlessly blended with iconic cityscape elements like buildings, streets, and landmarks. Utilize the watercolor technique to infuse the illustrations with soft, natural textures and a rich color palette, capturing the essence of both autumn and urban