This is an auto-coloured view of downtown Ottawa looking south from the Sappers' Bridge, that is to say the southern limb of the Plaza Bridge, Confederation Square. As to provenance, I can only say that I found the black-and-white original on the Twitter feed of some guy who lifted it off the Flickr of some other guy. Photoshop did the colour workup, giving us something suggestive of an old hand-coloured postcard. Click on the image to load a higher quality image.
I'm not sure of the date, but "towards the end of The War" would be a good starting point, given the style of the cars and the glimpse of the Temporary Buildings behind the Lombardy poplars on what is now Marion Dewar Plaza at the upper left.
The chateauesque Lord Elgin Hotel is easily recognised at the upper right of the photo, as is the spire of the adjacent First Baptist Church at 140 Laurier Ave West.
An intriguing feature is the chimney-stack on the horizon, left of center. This landmark structure was part of what was once a government-operated office-furniture factory on the south side of Isabella St. The chimney marks the present position of the NW corner of the Loblaw's store just south of the Queensway, between Elgin and Metcalfe.
The various multi-storey buildings on the right side of the image remind us that Confederation Park was once home to a healthy concentration of apartment and office buildings.
The red brick shamble is Ottawa's "old" police station, sited smack-dab in the middle of what is now the NAC. For more on this subject, please do check out Chris Ryan's discussion here.
The signature roofline of the former cop-shop makes an appearance in a photo (again colourized) taken by my father in the spring of 1955.
The POV is clearly the SE corner of the Parliament Hill lawn, looking toward the War Memorial on a wet April afternoon. Okay, I'm guessing about the afternoon, but the crocuses have finished blooming and the elms are just starting to bud out. Easter fell on April 10th that year. Just saying.