It’s still around, but the Seneca Niagara Casino at 358 feet is much taller.
The tallest building in Rochester is the 443 foot Xerox Tower. That may be the best place to view the CN Tower from or vice versa. I don’t think you can, though.
Is it possible to view (without the use of a device or technology) any part of the USA from Toronto?
Buffalo is closer to Toronto than Rochester (60 miles vs. 90), and has a taller building (529 feet). The base elevations are comparable.
The difference is that Buffalo is many miles inland. Downtown Rochester is only a few miles from Lake Ontario with no high spots in the way. The clear view across the lake is what makes many people say they can see Toronto.
As I said, though, I don’t think it’s true.
No, you can definitely see Toronto from New York. You don’t even need any elevation. I’ve stood on the beach on Olcott and seen Toronto on a clear day.
The problem is that Rochester is well to the east of Toronto. If you were in the Xerox Tower looking in the direction of Toronto, you’d be looking almost straight west towards Gates.
The nearest point to Toronto that is in New York is about 32 miles away. That’s the lakeshore. At 32 miles, something would have to be roughly 682 feet tall, just to see the tip top of it on the horizon. That in reality means it would have to be substantially taller for it to register in your sight (at 32 miles away, something 100’ tall would look as big as something less than one inch tall would from 10 feet away; in other words, hardly noticeable). From the New York lakeshore, the CN tower would certainly be visible on a clear day. Nothing on the New York shoreline would be visible from ground level in Toronto. (In making these calculations, I am treating a ground level observer as if they are 0’ tall; the 6’ or so of height does not change the equation very much at all).
Now, if the person observing has gained some elevation, the geometry changes. To know how tall something would have to be if you are, say, 150’ in elevation, it has to get above the tangent drawn from your eyes to the ground-level horizon (represented by the lake level), which after touching the lake at one point, immediately begins to rise “up” in relation to the surface of the globe. This entails making two right triangles. The first is used to determine the distance from you to the horizon, and the second is used to determine the height of an object that has its top exactly at the horizon at the distance you are discussing. Using the 32 miles from before, and approximating the radius of the Earth at 3960 mi., at 150’ elevation, you would see about 15 mi. to the horizon, thus the short leg of the other triangle is 17 mi. With this geometry, you could see anything taller than 192 feet on the New York shore, though again, it would have to be substantially taller to register in your unaided sight.
From the CN Tower, at 1465’, you can see not quite 47 mi. to the horizon. At 32 mi., therefor, you would be able to see the shore of New York. At that distance, something 150’ tall would have its tip level with the distant horizon.
Downtown Buffalo is 60mi. from Toronto, so it’s doubtful you can see Buffalo’s buildings even from the CN Tower. Downtown Rochester is 90 mi. away; at that distance, even from the CN Tower, a building would have to be as tall as the CN Tower to even have its top rise to the level of the horizon.
Isn’t similarity of triangles wonderful? 
I’ve been wondering if there’s a trivial answer to this thread, e.g., the building in question is across the street from the American consulate, or something.
Not the Consulate anyway. It’s over three miles away from that intersection.
And there’s a business called United States Virgin in Toronto (it’s a subsidiary of Virgin Airlines) but its offices are farther away than the consulate’s.
Maybe the OPs friend is Sarah Palin.
There’s also the possibility that you might get a fata morgana mirage or similar effect, that could (under just the right circumstances) extend your horizon distance beyond the geometric limit.
On a clear day, there’s at least one building in Rochester that I’ve seen from Toronto. My friend told me it’s a power plant; you can see the smokestacks.
EDIT: A quick Google search suggests it’s actually the Kintigh Generating Station in Somerset, NY. So my friend was wrong about it being in Rochester.
I’ve seen the mist-cloud of Niagara Falls from the CN Tower.
There are three RG&E hydroelectric power plants in Rochester. But they’re all down next to the river which runs well below street level (2, 5, and 26). You can barely see these plants from Rochester let alone Toronto.
The only other power plant near Rochester is the Ginna Nuclear Generator. It’s not actually in Rochester but it’s nearby (coincidentally it’s in the town of Ontario). It’s on the lakeshore but it’s not a tall building that you’d see from any great distance.
Good to know. Plus, Somerset NY is a fair bit closer (and hence plausible to see) than Rochester.
So to answer the original poster’s question: I would not be surprised at all if someone claimed they could see the smokestack of Kintigh Generating Station with a plume of warm air coming out of it from an apartment building at Bathurst and Eglinton. Whether that counts as “seeing the United States”, I wouldn’t venture to say.
Did the person specify naked eye or do they have a telescope or the like?
A telescope shouldn’t matter. The limitation isn’t distance, but the curvature of the Earth.
Look up when the moon is out. There’s a bunch of U.S. flags planted on it.
(Just kidding; the U.S. expressly didn’t claim the Moon and is a signatory to the Outer Space Treaty).
The Wikipedia article on the CN Tower claims that
It’s been quite a while since I was up there, and I don’t recall what you could see.
For that matter, I ate at The Changing Scene atop First Federal PLaza in Rochester. I can’t recall if I could see the CN Tower, but I think I’d have remembered if I could.
FYI, here’s a horizon distance calculator (not that the math is very hard, but this is convenient)