The nuclear-powered Project 949A Antey submarine K-141 Kursk sank in an accident on 12 August 2000 in the Barents Sea. It was taking part in the first major Russian naval exercise in more than 10 years. All 118 personnel on board were killed. (Wiki)
A short moment in an interview with Larry King, for which Putin has been widely critized.
Short Spiegel summary.