Elephants! What a lovely end to the working day. We collected our last hydrophone and made the last measurements upstream, and then on the way back SO MANY elephants had come down to the river to cool off. Do listen with the sound on - there's proper trumpetting. 🐘🐘🐘🐘

If you have ever doubted that water really *is* blue, here's a photo of a meltwater pond on a glacier in Greenland. The water is pure, and the white background makes the colour obvious. You need a lot of clean water to see it, but the true colour of water is an incredibly striking brilliant blue.