class

until and unless you have done class II or class III, you really can not judge or imagine what beauty would class IV and how scary would class V and class VI be. may be class V and class VI would be more scary than i can imagine, but i am still too tempted to resist giving the classification of rapids in white-water that i found on multiple sites. may be this is the official classification.

Rapid Classification:-

Class I - Small rapids with low waves and no obstructions
Class II - More frequent rapids with few or no obstructions
Class III - Waves up to four feet, with some maneuvering around obstructions
Class IV - Very difficult, extended rapids. Scouting is necessary.
Class V - Long and violent rapids. Large waves which are unavoidable. Complex course. Scouting is a must.
Class VI - Maximum difficulty. Involves serious risk to life.

i feel proud that i have done class III rapids :D