They call it the “Grand Canyon of Siam” and some have even compared it to the surface of the moon: a continuous current of rock notched with 3,000 holes, known in the Lao/Isaan language as Sam Phan Bok. Though difficult to reach in a distant corner of Ubon Ratchathani province, the other-worldly landscape and Mekong River scenery make it worth the effort. The 3,000 impressions (certainly it’s an exact count!) look like they were carved out of the rock by a giant ice-cream scooper — a landscape that would make a fine filming location for a sci-fi flick set on the surface of another planet. Sam Phan Bok (it rhymes with “on Ron’s joke”) doesn’t look anything like the real Grand Canyon, but it certainly is one of a kind. Much of the rock submerges during the rainy season in an ancient process that helps to polish and sculpt the cavities. Turning into miniature mirror-like ponds of rainwater in May and June, some of the holes are shaped like hearts or Mickey Mouse’s head. When dry, locals lay down mats to enjoy a meal in some of the larger and comfier depressions. Dry season also sees the Mekong narrow to a mere 56 metres across, supposedly its narrowest point south of China.