When Scottish actor Mark Bonnar was growing up, he thought it was normal to have a father whose job was to create concrete hippos for new cities.

His father Stan Bonnar was one of the first Scottish artists specifically employed to make works of art for the new cities that sprouted across the country in the 1970s.

“It was a fascinating way to grow up,” says the actor, who recently starred in the BBC’s second series of Guilt.

“My memories are of wide open spaces and unusual objects.”

In the years following World War II, Scotland designed five totally new cities in an attempt to displace people from overcrowded slum conditions in parts of Glasgow and other cities.

East Kilbride, Glenrothes, Cumbernauld, Irvine and Livingston were great planning solutions that would completely rethink the look of cities.

In 1968 Glenrothes in Fife became the first new city in the world to hire a dedicated city artist when it named David Harding.

Harding was an “environmental artist” whose motto was “no plinth”. Her art was on the ground for people to touch and climb. It was as much a part of the environment as the trees and street lamps, but it was also an art that could thrill and inspire.

In his senior year at art school, Stan Bonnar became Harding’s apprentice and his first job was a series of concrete hippos that are still in town to this day.

Mark and his father returned to hippos for the BBC Scotland documentary Meet You at the Hippos.

Stan says it was great to see them again after all these years.

“I hadn’t really seen them since they came out of the mold and they were bright and shiny,” he says.

Five decades of Scottish climate have darkened their color, but Stan says they still look good if you look at them correctly.

“Going back and seeing them with the Glenrothes skies nestled in their backs was truly amazing,” he says.

Stan says he is “happy beyond words” that the hippos have become something of a town mascot for Glenrothes.

Mark, who has also starred in Line of Duty, Unforgotten and Catastrophe, says it was “very special” to see his father’s reaction to all of this.

After a year in Glenrothes in the early 1970s, Stan Bonnar went to East Kilbride to be their new town artist.

Stan and Mark have revisited the concrete elephants he made during his stay there. They are still in position but everyone has lost their trunk.

“I see them now and I know why they broke,” says Stan in the documentary.

“I should have thought that the logs needed to be a little stronger so that people, if they wanted to, could jump on and off them.

“But I made them a little too thin, so I’m very sorry for that.”

Also the artist, 72-year-old Stan, says that the broken logs are now part of East Kilbride and the elephants are now even more part of the environment.

After East Kilbride, Stan became a member of the main design team for a planned new town at Stonehouse in Lanarkshire.

In 1976, Stan moved into the first houses built in the town with his children, but a few days later the big plans for Scotland’s sixth new town were canceled and it was never built.

The concrete elephants that Stan made are still there and their trunks are also broken.

Looking back at what his father has been trying to achieve, Mark says he has a new respect for his work.

“If nothing else, I hope it draws people’s attention to a new way of seeing art,” he says.

Meet You at the Hippos in BBC Scotland on Tuesdays at 10pm and on iplayer.