Koh Rong Sanloem is a roadless island of white sand and jungle hills off the Cambodian coast, an hour by boat from Sihanoukville. It is narrow enough that you can walk across it in half an hour. Saracen Bay is the long pale crescent on the east coast, named for HMS Saracen, a British ship that charted these waters in the late 1800s. The bungalows stand back under the coconut palms, and a forest trail crosses the ridge from there to Sunset Beach on the west shore. That side faces open water instead of the ferry pier, so the crowd thins to a handful of long-stay travellers. As the light drops the sky behind the palms goes copper and pink. Other paths climb to hill viewpoints where both coasts show, jungle ridges on one side and the bay on the other, and from up there you finally see how little land there is.
A kayak takes you out of the bay to coves no trail reaches, sandstone rock meeting clear water. With some thirty-seven kilometres of coast there is another empty beach around each headland. There is one hard story here as well. In May 1975 the Khmer Rouge seized an American cargo ship, the SS Mayaguez, and held its crew on this island. US forces stormed Koh Tang next door expecting to find them, in what is counted as the last battle of the Vietnam War. The thing the island is known for only happens once every light is out. On a moonless night you walk into the sea and every stroke sets off a spray of cold blue-green sparks; by day the same water is simply clear. It needs real darkness, so it shows best away from the jetties and bungalow lamps, in the dry months when the sea is calm. Power here runs in patches and no street lamp stands anywhere on the island. So you wade out from a beach with nothing lit on it, and what lights up is the water around your legs.