I will expand on my alternate history of Winnipeg and Manitoba, but instead of using the 5 million figure that reflects the optimism of the times I will use what I believe to be more realistic.
Despite the opening of the Panama Canal, Winnipeg suffered only a minor blip in its boom, growing to 300,000 by 1921. The 1920's saw a resurgence in growth, many of the city's older skyscrapers were built during this era, including the four at Portage and Main that rise to about 30 floors each. By 1931, the city had grown to 500,000. The city struggled during the Depression years, but rural flight increased the population still to 600,000 by 1941. The Second World War saw a manufacturing boom occur in the city, with the effects of this boom most visible in and around St. Boniface and Transcona. The post-war baby boom also increased the city's population during the 1950's so that by 1961, the city had grown to 1 million. By the mid-1960's, the area within the city limits had been entirely developed, most of these neighborhoods dated to before the Second World War. Waverley West, Wilkes South and Old Kildonan were the main developments in the city after the war. During the 1960's the migration to the suburbs began, this saw Headingley and both East and West St. Paul to develop, and these suburban municipalities are part of the city's continuous built up area. The Manitoba Capital Region composes of Winnipeg's metropolitan area and is home to 2.5 million people. The population within the city itself is 800,000, up from its low of 750,000 in 2001.
The South Broadway neighborhood functions as the city's business district and is composed of primarily midrise office buildings. A few skyscrapers over 150 metres are located in this neighborhood, the tallest building in the city soars to 60 floors.
The Exchange District is much larger on its west side and relatively intact and a tourist draw. The east Exchange was razed in the 1960's and 1970's as a result of "modernization".
West Broadway and Point Douglas are some of the hottest neighborhoods in the city. Many of the blighted houses were demolished in the 1990's and have been replaced by new low to midrise condo and apartment buildings. These neighborhoods are popular among the "artsy" community.
The area around Central Park is seeing the construction of many new condo and apartment towers (picture Glasshouse and Dcondos).
The North End is the most blighted area in the city and has the highest crime and poverty rates. The area east of main is gentrifying and property values are increasing as young families move in.
Elmwood and Transcona are also quite blighted, however there further distance from the resurgence happening downtown means they will continue to decline for the next few years.
The city's wealthiest neighborhoods are those located along the rivers on the south side of the city.
Imagine Winnipeg being similar to Minneapolis / St. Paul.
Brandon
As Manitoba's population boom continued for a longer period in the early 20th century, it became the hub for a larger area and main city in between Winnipeg and Regina. By WW2, the city had grown to 50,000 and has continued to have healthy growth since, exceeding 100,000 by the 21st century. Imagine Brandon being similar to Fargo.
The Pas
With the construction of the HBR to Churchill, the city population boomed and by WW2 was Manitoba's "third city". The city has been in relative decline for the past few decades, but the population has remained stable at 50,000 thanks to a growing urban Aboriginal population. Unfortunately, the city is plagued by the highest crime rates in the province and has one of the highest poverty rates among all communities in the province. Imagine The Pas being similar to Prince Albert.
Churchill
Churchill was little more than a remote outpost at the mouth of the Churchill River until the 1930's when it's port opened. The city boomed in it'd early years, despite the port being unusable foruch of the year. The city became a strategic location during the Cold War which gave boost to its economy when it would've been in decline. The city has approximately 50,000 residents. Imagine Churchill being similar to Thunder Bay, but half the size.
Portage la Prairie
Portage la Prairie is the hub city in between Winnipeg and Brandon. It has been relatively stagnant since the 1960's, but has grown to 50,000 in the past few years.
Other important cities in Manitoba would be Selkirk (pop. 30,000), Dauphin (pop. 30,000), Emerson (pop. 20,000), Neepawa (pop. 10,000), Carman (pop. 10,000), Morden (pop. 10,000), and Souris (pop. 10,000).
The following communities would have about 5,000 residents:
Beausejour, Gimli, Virden, Swan River, Roblin, Manitou, Killarney, Boissevain, Deloraine, Melita, Carberry, Glafstone and Minnedosa.