From Wilcannia, you can branch off the Barrier Highway, heading north along a road partly sealed for 30km, and then graded gravel for the final 67km to the opal fields at WHITE CLIFFS , 97km away. Besides opals, White Cliffs is famous for the extraordinary summer heat, and for the way in which the miners have avoided it since the 1890s (when about four thousand lived here) - many of the approximately two hundred residents live underground in so-called "dug-outs", where it's cool in summer and warm in winter. There are all sorts of underground attractions, as well as a high-tech attempt to exploit the climate in the form of an experimental solar power station. For the authentic underground experience, there are two places to stay: the original and very friendly White Cliffs Dug-Out Motel (tel 08/8091 6647 or free call 1800 021 154, fax 8091 6654, underground.motel@telstra.com ; $70-90), which comes complete with licensed restaurant and outdoor swimming pool; and the only subterranean B&B, PJs (tel 08/8091 6626, www.babs.com.au/nsw/pj.htm ; $90-115), where you have to share a bathroom and take off your shoes. Cheaper, above-ground options are the White Cliffs Hotel (tel 08/8091 6606, fax 8091 6782; $35-50) and the Family Inn at the Post Office (tel & fax 08/8091 6645; $35-50). If you can bear the heat, there's also camping (with hot showers) at Opal Pioneer Reserve, close to town. Tourist information is available on Keraro Road at the White Cliffs General Store (daily 8am-7pm; tel & fax 08/8091 6611).

There are several tours to White Cliffs from Broken Hill; otherwise you'll need your own transport to get here. The only fuel stop between Wilcannia and Broken Hill is at the Little Topar Hotel , roughly halfway along the 195-kilometre stretch of the Barrier Highway.