Nearly half the rapids on the Zambezi River below the Victoria Falls are classified as Grade 5 (Grade 6 is commercially unrunnable), which means that the steep gradient of the river causes long and extremely turbulent rapids with big drops and a high volume of water. For those that want even more adrenalin than the white-water rafting can give, river boarding allows individuals to surf their way down the mighty Zambezi armed with only a body board, fins, helmet and lifejacket. The big attraction is the physical freedom and the sense of achievement felt after tackling the Zambezi on your own.