For those who don't know, Angel Falls is the highest waterfall on Earth. According to Wikipedia, it drops almost a full 1000 meters and wasn't even discovered until 1933. They are located in a very high-wilderness national park region so I think the only way to really visit them is to go by plane from Caracas to a smaller town on the outskirts of the park and then travel up the river by boat.
Wikipedia states the falls cannot be seen on cloudy days and there is no guarantee a visitor will see them. During the dry season (December to March) there is less water than that seen in some photos, but it also more likely that the top will not be clouded. The entire trip usually takes 24 hours.
It would be nice to get some input from anyone who has been there or is more familiar with this region.
Here's an image of the falls. They are quite spectacular. :)