The Yellow River, China

Laoniu Bay sits at the junction of Shanxi Province to the south and Inner Mongolia to the north. It is where the Great Wall meets the mighty Yellow River and then runs alongside it for the next 44mi (70km). A lone, ruined beacon tower stands at the end of the headland. 

The Yellow River has an amazing journey across China. Its source is in the Bayan Har Mountains, Western China at an elevation of 15,700ft (4,800m) and it flows east until it empties in the Bohai Sea. It is the second longest river in China, after the Yanghtze, and the sixth longest in the world. 

Heading east, the river runs through two large freshwater lakes, Gyaring and Ngoring. The water is crystal clear with a steady flow. It then makes two loops, first is northwest, followed by northeast, before it takes a sharp southern turn until it turns east again for its final flow into the sea. 

The upper river travels through pastures, swamps, knolls and peat bog. The terrain along its banks changes from steep cliffs to deserts and grasslands. When it reaches the middle section, the river runs through the Loess Plateau, where large amounts of mud and sand end up in the river, giving it the muddy-yellow colour. Each year approximately 1.4 billion tonnes of silt are carried to the sea. In 1933, a record 3.9 billion tonnes of silt were discharged into the river from the plateau. The flow here is powerful, making it a great location for hydroelectric plants. When it reaches the lower section, the river slows down and sometimes it even dries up before reaching the sea. 

The Yellow River has flooded many times, causing enormous losses of life and destruction. It has also been used as a military tactic by sabotaging canals and reservoirs or intentionally flooding warring states. Sometimes such plans backfire, as it did in 1642, when a Ming governor ordered  the dikes to be broken in the hope that it would flood the rebels. Instead, it destroyed his city, causing famine and a plague that killed nearly 80% of its population. 

Over the course of the last 2,500 years, it is estimated that the Yellow River has flooded nearly 1,600 times. It has also changed its course noticeably 26 times and severely at least 9 times. The most significant change was in the 12th century when instead of flowing into the Bohai Sea, as it usually does, it shifted so far south that it flowed into the Yellow Sea. It took 700 years for the Yellow River to return to its more northerly course.