Design a rich, girly poster of Boston with a retro vibe, densely filled with hand-drawn landmarks and symbols of the city in pastel colors. Feature the historic Freedom Trail, quaint cobblestone streets, and iconic brownstones, each intricately stylized amidst a vibrant backdrop of autumn leaves and colonial lanterns. Integrate subtle heart-shaped silhouettes and the serene Charles River to evoke a sense of sweet nostalgia. The composition should be lively and detailed, capturing the unique charm and historical depth of Boston in a crowded yet harmonious display." --niji 6