A native of Communist China who immigrated to the United States with his family as a child, Lee Hsia is leading a new underground church, not in China, but in downtown Houston, 20 feet below the city’s streets. Hsia is launching a campus of First Baptist Church in Houston’s six-mile tunnel system that links office buildings, restaurants, shops, convenience stores and residences. “When we launched last fall, I thought we’d have mainly young people in their 20s and 30s,” Hsia said. “As it turned out, we have people of all age groups and all kinds of ethnicities. At last count, 33 nations are represented.”