Between Pai & Mae Hong Son
Either as a day trip from Pai or as a stop on the way to Mae Hong Son, the best little detour going is the lod, or Spirit Cave, off Route 1095 (about 30km/18 1/2 miles northwest of Pai on Route 1095 in the town of Soppong, and then about 8km, or 5 miles, north of the highway). This large, awe-inspiring cave filled with colorful stalagmites, stalactites, and small caverns will keep you exploring for hours. The cavern was discovered in the 1960s jam-packed with antique pottery dating from the Ban Chiang culture. There are three caves. The first chamber is a magnificent grotto and the second contains a prehistoric cave painting of a deer (which unfortunately has been largely blurred from curious fingers). The third cavern contains prehistoric coffins shaped like canoes. A guide to all three caves costs 100B (US$2.85/£1.55), with lantern rental included. Be sure to take the canoe ride to the third cave (the ferryman will hit you up for an extra 100B/US$2.85/£1.55) where, especially in the late afternoon and evening, you can see clouds of bats and swallows vying for space in the cave's high craggy ceiling (the boat ride is fun, too). Pay again to get back by boat or you can follow the clear jungle path a few clicks back to the parking lot. Bring your own flashlight for self-exploration as well.
There are lots of little guesthouses along the road near the entrance to the Spirit Caves in Soppong; the best is the friendly Little Eden Guesthouse (295 Moo 1, T. Soppong, tel. 05361-7054; www.littleeden-guesthouse.com). They have basic bungalows around a postage-stamp pool, as well as an authentic rustic suite overlooking the river (450B-1,500B/US$13-US$43/£6.95-£23).
As the road curves south heading into Mae Hong Son, Tham Pla Park (17km/10 1/2 miles north of Mae Hong Son on Rte. 1095) is a small landscaped park leading up to the entrance of Tham Pla, or Fish Cave. It is a small grotto crowded with carp (legend says there are 10,000 of them) that mysteriously prefer the cave to the nearby streams. You can buy fish food in the parking lot (10B/29¢/14p per packet), but the fish don't eat it. Have a look -- it is meant to be good luck (also a good leg stretch after the long drive). The grotto, once unsuccessfully explored by Thai Navy divers, is said to be several meters deep and to extend for miles.
Ten kilometers (6 miles) away in the Tham Pla Park interior is the huge Pha Sua Waterfall, which tumbles over limestone cliffs in seven cataracts. The water is at its most powerful after the rainy season in August and September. The Meo hill-tribe village of Mae Sou Yaa is beyond the park on a road suitable for Jeeps, just a few kilometers from the Burmese border.