The Stockholm City Museum (Stadsmuseet) documents, preserves and exhibits the history of Sweden's capital. It has invited people who were in the city on April 7th to send them their memories, images, videos, conversations and posts on social media related to the attack in order for them to be collated and preserved.
All Stockholmers are welcome to participate, as are people who were in other cities and had contact with loved ones who were in the Swedish capital when the attack happened.
"One of our duties is to document the present time for the future. That usually means a focus on everyday life, but when an incident like this happens we want to help preserve thoughts, reflections and photographs for the future," Anna Ulfstrand, the head of the documentation department at Stockholm City Museum, told The Local.
The special website set up for the project offers three ways to contribute. Photos can be uploaded, stories can be left, and screengrabs of Facebook conversation threads can also be submitted.
"The first step is to collect everything and archive it. We'll also publish material continuously," Ulfstrand explained.
"It's too early to say what we'll then go on and do with it. Perhaps there will be an exhibition, book, or something different. Material will also be available to researchers and the general public."
The different forms of material will be treated in different ways: images submitted will become public property and could therefore be used in exhibitions. Screengrabs of conversations will not be made public but could be used in future research, while stories will be used in documenting the day and may be made public, but can be left anonymously if preferred.
Some of the stories are already available to read on the project's Tumblr page.
On Monday the piles of flowers, stuffed toys, candles, flags and messages left on Drottninggatan and Sergels torg in tribute to the victims were removed after lying in place for over a week. Some of those items were collected as part of the museum's project and will be archived.
And the museum is keen to hear from Stockholmers who reached out and helped others left stranded on the day of the attack, like those who opened their homes to strangers using the "OpenStockholm" hashtag on social media.
"We're also very interested in those kind of stories and images," Ulfstrand noted.