China's sinkholes: Tourist boom threatens ancient forests

Xiqing Wang/ BBCSinkholes in China's Guangxi province have become a tourist attraction The couple stands on the edge of the sheer limestone cliff.More than 100 metres (328ft) beneath them is a lost world of ancient forests, plants and animals. All they can see is leafy tree tops and hear is the echoes of cicadas and birds bouncing off the cliffs.For thousands of years, this “heavenly pit” or “tiankeng”, in…