Allen Riedel Special to Valley News Ghost Mountain in the Anza-Borrego Desert State Park is the home of a unique piece of Southern California history. Halfway up the spine of the mountain, hikers will find the remnants of Yaqui-tepec, a one-of-a-kind desert experiment concocted by Marshal and Tanya South, an author and his artist wife. The couple left civilization in 1930 to raise their three children amongst the harsh desert environs, unspoiled by what they saw as the callousness of society. There, they felt freed from the confines and pressures of modern life. Ultimately, the couple split after their 17-year undertaking, and the children do not talk of their life there to this day. The hike, with a difficulty rating of easy, covers 2 miles roundtrip and takes about 1 hour.