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. Half and full-day rafting expeditions provide what is internationally acclaimed to be the wildest and best white-water rafting experience in the world. The most exciting time to do rafting is during the dry season (July to mid-February) when the water is at its lowest and the rapids at their biggest. For those that want even more adrenalin than the white water rafting can supply, river boarding allows individuals to surf their way down the mighty Zambezi armed with only a body board, fins, helmet and lifejacket. The attraction is the physical freedom and the sense of achievement felt after tackling the Zambezi on your own.