The falls' total height is 21 metres (69 ft) in segmented cascades (or rapids) stretching 9.7 km (6.0 mi) of the river's length. The average discharge of the cataract is nearly 11,000 m3 (388,000 cu ft) per second (3 million U.S. gallons per second), though the highest volume on record was reached at over 49,000 m3 (1,730,419 cu ft) per second (13 million U.S. gallons per second).
The area of the falls is dotted with islands and countless waterways, known as Si Phan Don (meaning 4000 islands).
The Khone Falls are well known as the prime reason why the Mekong river is not navigable into China. In the late 19th century French colonialists made repeated efforts to navigate the falls but they all failed. The first time they succeeded in bringing vessels of any size to the part of the river above the falls was when they had built a railway between two islands on the falls, circumventing the steepest rapids and allowing trans-shipment.
The falls are home to the plabuck, an endangered species of catfish said to be the largest freshwater fish in the world. The plabuck is alleged to reach lengths of 3 m (10 ft) and weights of up to 646 pounds (293 kilograms).
Si Phan Don (Four Thousand Islands) is a group of islands in the Mekong River in Southern Laos.Source, Images: http://en.wikipedia.org/wiki/Khone_Phapheng_Falls