At Las Cruces, a city booming on cotton, rockets, and tourists, Interstate 10 turns south to parallel the east side of the Rio Grande Valley down to Texas and El Paso. If one prefers a quiet scenic route, State Highway 28 winds its way along the west side of the Valley amid fields and groves, through peaceful villages, to end at the bridge over the Rio Grande on the edge of El Paso. Here, to the south, is El Cristo Rey, a cone of massive andesite, flanked by steeply tilted beds of limestone and shale, Early Cretaceous in age, cut in two by the New Mexico-Mexico border. Atop the peak is a 29-foot-high, 40-ton, limestone statue of Christ; a winding path leads upward from the base for those strong enough of limb to make the climb. Beyond, to the south, Ciudad Juarez lies, famous for its bordertown flavor, markets, cathedrals, and bull rings. The traveler to the east should stay on U.S. 62-180 from El Paso. This highway cuts through the Hueco Mountains via Powwow Canyon, a gash carved from Pennsylvanian and Permian limestones, crosses the Diablo Plateau, rolls past the white patches of Salt Flat lakes, then winds up to the summit of Guadalupe Pass between the Delaware Mountains on the south and the towering Guadalupe Mountains on the north. Looking north from the Pass, Guadalupe Peak, highest point in Texas, and El Capitan are unforgettable sights, their steep lower slopes ribbed brown and green, overshadowed by the 1000-foot limestone cliffs of the peaks. The limestone-hewn Guadalupe Mountains parallel the highway in New Mexico and are pitted with many caves, with Carlsbad Caverns the largest known in the range. Eastward beyond the Pecos Valley stretches the Great Plains and Texas. A side trip, near Carlsbad, over black-topped and gravel roads leads from Seven Rivers, up Rocky Arroyo on State Road 137, into the northern foothills of the Guadalupe Mountains to Sitting Bull Falls. Here, cool spring waters cascade over limestone ledges to join in green pools lying amid the cottonwood groves of the canyon floor. Lake McMillan, a reservoir along the Pecos River north of Carlsbad, and the many potash mines east of Carlsbad are parts of the enchanting landscapes of this southeastern corner. Northward, following the green cotton fields bordering the Pecos River, U.S. Highway 285 leads through Artesia with its oil refineries to modern booming Roswell, second city of the state. East of Roswell, bordering the east side of the Pecos Valley, is Bottomless Lakes, azure blue pools spotted in sink holes.