This valley has high cliff walls. It is sometimes called the valley of 72 Waterfalls and is popular for hiking/tourism.
http://www.myjungfrau.ch/en.cfm/sommer/offer-So_Themenwege_JRM-Natur_Kultur-326178.html
The cliffs are used for BASE jumping. There have been several fatalities according to the list:
http://www.blincmagazine.com/forum/wiki/BASE_Fatality_List
http://www.basejumper.ch/index.php?option=com_content&task=view&id=12&Itemid=26
This German article suggest that there were four fatalities in the Valley in 2009 alone.
http://www.blick.ch/news/schweiz/bern/41-jaehriger-basejumper-prallt-an-felsen-tot-134547