Planters in the mall. Did that in Ontario in the 80s. Didn't get very big though; got pulled out.
One here in the early '90s was fairly substantial before it disappeared. I think maybe the janitors were taking care of it, lol. It's a shame I didn't have any auto-flowering seeds back then (no bud on a photoperiodic plant in a building that's well-lit for ~17 hours/day.
I did have one in the little concrete planter outside the front door to the local police station look like it was starting to flower, but I guess the cops got tired of watching to see who paid a significant amount of attention to it (I just glanced at it as I walked by once or twice per week). Or else one of the LEO took it home to... investigate it on a more personal level, IDK. That location is too well-lit now (and, yes, video cameras...), though.