This was done exactly 2 years ago, April 9th 2019, in Shoreditch, London in a prime location for street art and it stayed up for about 3 months, with pictures of it flooding the internet.
This is the picture I took right after I finished the bomb.
I scan the portraits and then I print large posters and wheatpaste them on the streets, these were about 6 feet long.
8858 x 5736 PNG