They are tremendously fuel efficient to bring to market, a fraction of the fuel cost of say, shrimp, and at the very top of the carbon efficiency scale.
They may only be a fraction of the height of the Himalayas, but they are still so dizzyingly steep that in many places it's almost impossible to get a foothold.
The president was told that if he settled for Yongbyon alone, he might appear to have been duped by the young leader of a country renowned for hiding pieces of its nuclear program in tunnels around the country.