which is the biggest water fall in the world?

ya its niagara

It depends what you mean by biggest. I think Victoria Falls is higher, but as to actual width and volume of water, I'm not too sure. I think you'll find Niagara is probably the third largest. Niagara Falls is neither the world's tallest nor broadest cascade, but it is among the most impressive and certainly the single most powerful. Its mile-long breadth makes Victoria Falls is Africa's biggest tourist attraction. At nearly 2700 feet, Angel Falls is the world's tallest and, located in the midst of the Venezuela's wild Gran Sabana region, perhaps the most remote.

I too think its Niagra