document: It collided with a cargo boat crossing the Padma river, about 40km (25 miles) north-west of the capital Dhaka.
  Most of those who drowned were on the ferry's lower decks - 40 or 50 people were rescued or swam ashore.
  Witnesses said the ferry may have been overcrowded, with up to 150 people reportedly on board.
  Accidents are common on Bangladesh's river network, with overcrowding and poor boat quality often to blame.
  The ferry was raised to the surface and brought ashore on Monday.
  The exact number of people aboard the boat is not known, as Bangladeshi ferries do not usually have formal passenger lists.
  Police have arrested three people, including at least one person responsible for steering the cargo vessel.
  Hafizur Rahman Sheikh, who survived the crash, told Bangladesh's Prothom Alo newspaper that many passengers were trapped on the lower decks when the ferry sank.
  A similar accident earlier this month killed at least seven passengers in southern Bangladesh.
  In August 2014 more than 100 people died when a ferry with a capacity of 85 capsized with more than 200 people aboard.
summary: At least 70 people are known to have died in a ferry accident in Bangladesh, after authorities managed to reach the vessel which capsized on Sunday.