Sinkholes seem to be opening up (or is that down?) all over the place these days and in this CCTV footage taken from the side of a bus, you can see two unlucky passengers finding the latest hole right underneath them. Taken in the Yongsan area in Seoul the hole was believed to be caused by water leaking out from the nearby wall weakening the pavement. Further tests will be carried out and construction records analysed before a conclusion as to the definitive cause is reached. Until then, mind your step.