Don't be alarmed if you saw a massive bomb rolling down an Alberta highway

If you were travelling along a highway south of Calgary on Friday, you may have gotten a glimpse of a replica of the largest bomb in the Second World War the Grand Slam, a behemoth that weighed 10,000 kilograms.

A full-size replica of a bomb called the Grand Slam wasmoved 90 kilometres along Highway 2,from Calgary to the Bomber Command Museum of Canada in Nanton.

The 10,000-kilogram Grand Slam was the largest bomb in the war.

The replica, which is constructed from fibreboard, aluminum and fibreglass, is eight metres long and about a metre wide.

It was built over three months by veteran woodworkersJohn Morel and Andy Lockhartin Morel's shop.

They normally buildhigh-end furniture, so when they were asked by the museum to make the bomb, they knew they could use their skills to pull it off.

Lockhart calls the replica bomb one of the biggest projects he's done.

"It had its moments,"Lockhart said, explaining that the materials were heavy and hard to manoeuvre.

"The tail part is sheet aluminum, bent from flat into a cone. And all of the various pieces had to line up with no gaps," he said.

"It's great to see it finally done."

Museum historian Dave Birrell says the Grand Slam bombs werecarried by specially-modified Lancaster Bombers with the elite Dambusters squadron.

"No other airplane could come close to lifting 22,400 pounds," he said.

The Allies dropped 41 one of them on German infrastructure targets such as rail bridges and underground submarine pens.

"Used in just that last few months of the war and the Canadian connection is that the leader of the squadron at that point was Johnny Fauquier, the most decorated Canadian airman in World War II," Birrell said.

Lockhart said he hopes the replica serves as a valuable teaching tool, and can foster "anappreciation of the scale of things that actually happened in World War II, the abilities of the guys who flew the Lancasters and did the missions, and some of the elements that actually went in to winning that war."

There are no other replicas of the bombs, but there are three or four originals at museums in the U.K., Birrell said.

The Grand Slam will be put on display alongside the museum's Lancaster bomber.