Fans of Meccano or those who want to relive a childhood hobby have until Friday to check out the work of local masters.
The MWT Meccano Club are displaying some of their work at Trafalgar Square this week.
Club member Viv Alexander said it had 25-30 members and was one of the biggest in the country.
Meccano - construction sets of metal parts with nuts and bolts - was first produced in 1901 in Liverpool.
"Meccano's still being made - you can buy it in shops," Mr Alexander said.
"It challenges your ingenuity. You've got some bits and pieces, now what do you do with them?
"It challenges you and develops you engineering ability and inventiveness."
He got his first Meccano second hand when he was seven and has been collecting since.
Meccano had changed a lot, he said.
It started as a number of standard parts but kit sets had been introduced over the years along with plastic and electronic parts.
Mr Alexander said it was not as popular with children as it once was.
"We'll have to think about how we can attract young people to it."
The MWT Meccano Club's display is on at Trafalgar Square from 10am to 2pm daily until Friday.
Just don't mention Lego.
"Lego is instant gratification," Mr Alexander said. "It's much simpler and doesn't challenge you anywhere near as much."