The wars were fought mainly along China's eastern and southern coasts and major waterways. The first included operations around Guangzhou, the Pearl River, and the Yangtze corridor toward Nanjing. The second extended north through the forts near Tianjin to Beijing, where invading forces occupied the capital and destroyed the Old Summer Palace. Steam-powered naval access to estuaries and rivers allowed foreign forces to threaten ports, inland commerce, and centers of government.