The car ferry M / S Estonia sank 26 years ago on September 28, 1994 in front of Utö on its way from Tallinn to Stockholm.
Of the 989 people on board, only 137 survived.
The accident killed 852 people.
Watch the ISTV documentary The Battle of Estonia for Life (2014) in the video above.
On the night of Estonia's accident, four other passenger car ferries visited the shipping route between Finland and Sweden.
Mariella and Silja Europa traveled west, Isabella and Silja Symphony traveled east.
Finnjet was on its way from Finland to Germany.
The first weak emergency call from Estonia left at 01.21.55:
"Mayday Mayday Estonia please."
Mariella tried to answer that.
At 01.24, the second emergency call was received by 14 radio stations - including the Turku Maritime Rescue Center, which took responsibility for the rescue operations.
Silja Europa got a radio connection to Estonia and Silja Symphony recorded the conversation.
Read here the discussion of the ships in English, Finnish and Swedish at the time of the accident, as recorded.
The documentary series Estonia - Revolutionary Discovery, released yesterday on Dplay +, shows how there seems to be a big hole on the starboard side of a sunken passenger ferry.
Authorities have previously disputed allegations of a hole in the hull.
Read more: The sight on the side of the wreck struck the authors of the Estonia documentary with an astonishment - “That's completely sunk in”
How did the hole get to Estonia's side?
A recent documentary brought up old conspiracy theories about destruction