Kim Jong-Un and Vladimir Putin vow to strengthen cooperation

<p>North Korea's Kim Jong-un spent more than 20 hours on an armoured locomotive to meet Russia's Vladimir Putin on his first trip abroad in more than four years. The high-profile summit between two of the world's most isolated leaders was held at a remote Siberian space centre. Washington has been closely watching cooperation between North Korea and Russia for over a year now. Yuka Royer takes a look at the event.<br/> </p>