London joined with communities across the country in commemorating the Battle of the Atlantic Sunday.

Each year on the first Sunday in May, Canada and its naval community remember the sailors, aviators, and mariners who died at sea during the Battle of the Atlantic, the longest campaign of the Second World War.

In London at HMCS Prevost, a parade and service was held to pay tribute to those lost.

The National Commemorative Ceremony took place at the National War Memorial.

The cost of winning the Battle of the Atlantic was high, with the Royal Canadian Navy losing nearly 2,000 sailors and 33 ships.

"We need to remember every year because the veterans who fought that battle become less and less every year. We need to honour them," says Lt.-Cmdr. Jeremy Breese.

"People say sometimes we don't learn from history so we have to keep that history alive and remember what people sacrificed to win that battle."