Photo of World War Commemeration - Installation on River Thames London and article.
The giant message has been created by The Royal British Legion to give thanks to "all who served, sacrificed, and changed our world." The artwork features 8ft (2.4m) high letters which include blank spaces for the public to add their own notes.
Today marks 100 days until the 100th anniversary of the end of the war.
The legion said they hoped the public would use the period before 11 November "to take part and find ways of saying thank you." It wants people to give thanks not only to those who fought and lost their lives but also the people who played their part on the home front.