We know from witnesses and reporting that the massive Beirut explosion earlier this week, which occurred when 2,750 tonnes of ammonium nitrate detonated, flattened much of what was within about a three-kilometre radius of the blast.
The sheer force flipped cars, blew out doors, broke windows and caused walls to collapse within five kilometres of the blast and reportedly broke windows as far away as nine or 10 kilometres from the Beirut port.
And people in Cyprus — some 235 kilometres across the Mediterranean Sea — said they heard the explosion and their windows rattled.
In Canada, the sale, transportation and storage of ammonium nitrate is carefully controlled by federal regulations, making a blast like the one that occurred in Beirut unlikely, Mario Tenuta, a professor of applied soil ecology at the University of Manitoba, told CBC News earlier this week.
But if it did occur, the maps below show how some cities with waterfronts or ports would be impacted.
Saint John, N.B.
The port in Saint John, N.B., is the third busiest by tonnage in the country. Thousands of people live within three kilometres of its port. And the city is home to the UNESCO Stonehammer Geopark — which features rocks and fossils that date from late Precambrian time a billion years ago up to the most recent Ice Age.
An Irving oil refinery lies within 10 kilometres of the waterfront. And were such an explosion to happen there, it would surely be heard — or even felt — across the Bay of Fundy in parts of Nova Scotia.
The Port of Montreal is a major industrial and commercial hub. And the city's famed Old Port occupies about two kilometres of the waterfront, home to some of the city's oldest architecture and tourist attractions.
Within three kilometres are several well-known neighbourhoods and landmarks, including the Latin Quarter, St-Laurent Boulevard and the Bell Centre. McGill University sits just outside the three-kilometre radius. But the effects of such a huge blast would possibly be felt as far away as the west-end neighbourhood of Notre-Dame-de-Grâce. It might be heard as far away as Ottawa.
Toronto's waterfront on Lake Ontario is densely populated, with about 65,000 people living on the city side and on the nearby Toronto Islands. There is a mix of industry, parkland and condos within three kilometres of the waterfront. Within five kilometres, there is Bay Street — Canada's financial district — as well as major tourist attractions and shopping.
But the destruction might reach as far away as the Yonge and Eglinton area. And the sound of the explosion might have been felt as far away as London, Ont., to the west or across Lake Ontario to Buffalo, N.Y, which sits on the eastern shore of Lake Erie
The city of Yellowknife is on the northern shore of Great Slave Lake. The airport is less than five kilometres from the waterfront, as is downtown Yellowknife, which is where most of the city's 20,000 residents live.
The cityscape features both highrises and original pioneer shacks, all of which would feel the impact of such an explosion. And were a blast as massive as the one in Beirut was to happen in Yellowknife, people hundreds of kilometres across Great Slave Lake in Hay River, N.W.T., might even hear it.
If an explosion like the one in Beirut happened in Vancouver's port, it would almost certainly be felt across the water in Nanaimo, B.C., or Victoria, perhaps even as far away as Port Angeles, Wash.
Within three kilometres of the Vancouver waterfront is Stanley Park, the popular Gastown neighbourhood and downtown Vancouver, home to about 62,000 people.
Less than five kilometres away is Granville Island, a popular market that is also home to theatres and artisan studios.