China’s enormous sinkholes are drawing huge crowds of tourists, but experts caution that the influx of visitors poses a serious risk to the delicate ecosystems within these natural wonders.

The sinkhole appeared in the afternoon on March 24 at an intersection in the Myeongil-dong neighborhood in eastern Seoul and injured a woman, identified as 48-year-old Heo Mo, whose van was ...

When the weakened surface collapses into the cavern, it creates a sinkhole. They vary in size, from very small to the huge one seen at Xiaozhai Tiankeng in China, known as the Xiaozhai Heavenly Pit.