The Great Wall of China extends over 6,000 km across northern China and is the largest human-made structure visible from space. The Forbidden City in Beijing was the royal palace during the Ming and Qing dynasties, covering 74 hectares within high walls and a moat. Yangtze River cruises offer attractions like visiting the Three Gorges, shore excursions, and seeing the Three Gorges Dam, with a vacation within a vacation on the cruise ships.