After the defeat of Napoleon and the, the victorious nations stripped the French of the immediate ability to make war on their neighbours.
Britain found itself with thousands of French cannons that couldn’t be used by British forces for the fear of sabotage, incompatibility and the need to keep the British armouries working.
It was decided to use them as street decorations in London and other towns and cities that had played a vital part in the wars. As these cannons were replaced over the centuries, the design was copied with the cannon muzzle ball. There are now part of the streetscape in most of our towns and cities.
In various British colonies, the same was done with excess defence cannons and captured French ships.
Wait, those things were cannon?
You’re telling me those are ACTUAL CANNONS?
I saw the resemblance my entire life, but assumed they were just made to look like them.