Church bells across Poland have tolled and an emergency siren has wailed to mark the minute a week ago that a plane crashed in western Russia, killing Poland's president, his wife and many of the country's civilian and military elite.
The plane crashed at 8.56am last Saturday, killing all 96 aboard and plunging the nation into deep grief.
The tolling bells were a precursor to a giant outdoor memorial later today in Warsaw's Pilsudski Square that is expected to draw hundreds of thousands of mourners.
It is the first of two days of sombre ceremonies.
Tomorrow, a state funeral for president Lech Kaczynski in Krakow is expected to be attended by nearly 100 foreign dignitaries, if the volcanic ash cloud emanating from Iceland does not hamper their travel.