Yoko Ono tweeted a picture of the glasses Lennon was wearing when he was shot and killed. One of the lenses is covered with his blood.
Ono's tweet said, "Over 1,057,000 people have been killed by guns in the USA since John Lennon was shot and killed on December 8, 1980."
Ono and Lennon were married 44 years ago on March 20, 1969.