In the next video of his current collection, Roman De Giuli takes us flying over liquid landscapes that look like our Earth in miniature. Many of them have the feeling of river deltas or glaciers. Sharp-eyed viewers will notice bubbles and flotsam in some of these streams. If you follow them, you can see how the flows vary — wiggling around islands, speeding up through constrictions and slowing down when the stream widens. It is, as always, a beautiful form of flow visualization. (Video and image credit: R. De Giuli)