The charity for blind and partially-sighted people has set up a massive screen at the Gyle Shopping Centre. They are showing images of iconic events, such as Neil Armstrong's moon landing, and asking passers-by what they would miss most if they lost their sight.
Director John Legg said: "It could be seeing your family grow up, reading a book, watching a favourite film. But it could also be losing your job, your income and your livelihood.
"Every week, ten people in Scotland start to lose their vision, but right now RNIB can only help one in three who need support."
The advert will be played on the giant screen all week to raise awareness of the RNIB's work. People can add comments or videos showing what they would miss at www.whatwouldyoulose.org.uk.