5 March 2017
The Marble Mountains [map] are a cluster of mountains just south of Da Nang, Vietnam. My wife Quynh (in blue), our niece An (in red), a student from our class Sinh (with the camera), and I hiked up one of the mountains and through some its numerous caves.
With steep climbs, loose stones, and sudden drops, it would be difficult for such an attraction to exist in a country such as the US. But in Vietnam personal safety is nobody's problem but your own, so the attractions are a lot more fun. Until you break your neck.
After a long flight I'm now in London, working on a new educational project at Google with my old friend Chris. This will keep me occupied for a while...