I wouldn't call it a "niagara falls", but there is a small waterfall. Walk up the stairs and to the back, you'll be at a wonderful view of a rocky "mountain" scene with water coming off a small section of it.
SPOILER BELOW:
The rocks aren't real. Just painted cement over a steel laticework. Forced perspective is used extensively here to make the "mountains" seem higher than they are. The trees are planted in giant tubs so that as they grow they can be moved to a lower spot, and new smaller trees planted in the upper spots to preserve the perspective effect.