Four college students were stranded near a deserted spot near the Great Wall in Huairou, Beijing, after they became exhausted.

They arrived there on Sunday morning and got lost on the way back. After they went in another direction, they reached a cliff and couldn't go on.

Fortunately, their mobile phones still worked at that moment, so they called police, who took 30 minutes to rescue them.

(Beijing Times March 5, 2009)