Up even earlier than the day before was rewarded by seeing a barely perceptible light before the sun rose over the horizon. After breakfast we transferred into a small boat for a down river ride through some of the Si Phan Don (4,000 islands) to Don Det (AKA Backpacker Central).
Once at Don Det we went for a walk around the island down to the old French Railway. After lunch, back in a boat across to a Nakasong (Ferry Boat Station) - ທ່າເຮືອ ນາກະສັງ, into a bus and off to the Khone Pha Pheng Waterfall - ຕາດຄອນພະເພັງ.
Si Phan Don (4,000 islands) is a riverine archipelago in the Mekong River, close to the Cambodian border. I couldn't find any information on how the islands formed, but I speculate that over time silt builds up, during monsoon season, in river rock cracks and crevices, during low water season plants start to grow providing a trap for more silt to deposit during subsequent wet seasons until an island forms in the river course. Some of these islands, over time, eventually join up. Exposed river banks show deep solid rich soil. The waters are home to the endangered freshwater Irrawaddy dolphin, which must have been in hiding when I was there. See Wikipedia.
The Old French Railway must rank pretty high on any list of colonial follies. The French erroneously thought the Mekong could be used as a conduit into China, until they faced their first barrier at the Khone Pha Pheng Falls. They attempted, and failed, to force a boat through in 1891, 1892 and 1893. After considering building a canal to go around the falls, the "French settled on a small portage railway across the islands of Don Khon and (later) Don Det, which would allow specially-designed vessels to be dismantled, transported on the railway, reassembled and launched further upstream." Track was laid and the railway opened in 1897, in 1910 a bridge was built between Don Det and Don Khon and the track was extended so that the route could be used all year round. In 1940 the railway ceased to operate.
