A rose tree and plaque in Glasgow in memory of Roma victims of the Nazis will be replaced with a granite plinth.Read more
In Auschwitz, Chancellor Merkel says remembering Nazi crimes "is part of German national identity".
Some six million are going to be made into a permanent public Holocaust memorial at the Lakes School near Windermere.
The school is built partly on the site of huts which, for a few months after World War Two, housed several hundred child survivors of the concentration camps, and the collection of buttons started as a history project.
Ken Pickering, a history teacher at the school, says they expected only a few thousand buttons from local people, but the appeal went worldwide, with a "tsunami" of all shapes and sizes coming in for months afterwards.
Trevor Avery, who founded the Lake District Holocaust Project to remember the stay of the children, says he is hoping the memorial will be finished in time for the 75th anniversary of the end of the war, next year, and that students will be "very, very involved" in the design.
The only thing I would stress, I would like every button to be involved in it, there's been talk about maybe to split it up because it's so huge, we could do one memorial here, one there, but I think the whole gathering of buttons is one pool of energy from around the world."
It's a unique site in Britain and also there's the emotional impact of the story, the trauma that those children who were evacuated here went through, I think that touched an enormous amount of people."
North London schools are being offered the chance to send two pupils and a teacher to visit the former Nazi concentration camp of Bergen-Belsen as part of a project to mark 75 years since its liberation by British forces.
The visits to northern Germany, which will take place in February and March 2020, are part of the Belsen 75 Programme and are intended to teach students about that period of history.
It is being run by the Holocaust Education Trust and UCL’s Centre for Holocaust Education who said fewer than 27% of the places for north London schools remain to take part.
Holocaust Survivor Susan Pollack, who was liberated from Bergen-Belsen in 1945 said: “If it wasn’t for that British soldier who picked me up and saved me, I wouldn’t be here today.
"On liberation, I was virtually a corpse, unable to walk, and would soon have died. It is our duty to tell others this story."
Speaking about the project Mayor of London Sadiq Khan said it offered "young Londoners a unique opportunity to reflect upon one of the darkest chapters in human history".
Schools are able to apply to take part in the visits here.