It was more than just a lie-in in a fancy hotel...
More than 40 years since Beatle John Lennon and his wife Yoko Ono staged their world-famous "bed ins" for peace, the events are still well remembered.
So much in fact, that this artwork from on the couple's duvet demonstrations is expected to bring up-to $100,000 when it auctions at Christie's.
Christie's sale will take place in London next Tuesday (November 15).
Peace of history: John Lennon's 'Bed Peace' art will be familiar if
The felt-tip pen on foam board art's provenance goes back to John and Yoko's seven-day "bed-in for peace" held in 1969.
The bed-in happened at the Queen Elizabeth hotel in Montreal, just two months after the couple's honeymoon bed-in in Amsterdam.
The world's media were invited - one of whom, a freelance sound man, took the piece as the event drew to a close.
This artwork was hung above the couple's bed next to a sign reading "Hair Peace". News footage by the world's media captured both artworks, immortalising both.
However, the "Bed Peace" sign was the only constant artwork during the Montreal bed-in. All of the others were given as gifts.
Lennon and Ono each signed the artwork which also bears caricatures of both drawn by John.
The newlyweds' bed in began in May 1969 and lasted a week. It was also notable for being the time the couple recorded their anthem Give Peace a Chance.
Both John and Yoko are no stranger to the more unusual side of collectibles. In the 1970s, the rock 'n' roll couple gifted their hair to a Black Power commune to help raise funds, realising the potential value of their locks.
Collectibles retailers like the website asmallpieceofhistory.com still specialise in celebrity hair to this day.
Or, if pre-Yoko era John Lennon is more your thing, then asmallpieceofhistory.com is also offering bed sheets slept in by all four Beatles at a Detroit hotel during their inaugral US visit.