Martin Park swings himself with a fearless jump onto the steep sloping roof.  He just wanted to quickly give the windows a wipe on the outside.  One hand holds on to the window frame while the other wipes the glass.  One foot feels for a grip, the other slips.  His breathing stops – no. “Pretty slippy up here” he states calmly and maneouvers himself into position again.  It’s an advantage that free-climbing is one  of his hobbies.  And maybe also that he can’t see the chasm below him… for Martin Park is blind.

Source: WDR press release

The episode can also be view in the WDR Mediathek.