This is a composite of downtown Toronto, Centre Island and lake Ontario, put together from photos taken from the CN Tower skypod, 443 m above the ground.
Three rows of 18 photos (54 photos total) were used in the composite. Final processing was about 8 hours on a P3/1GHz/1GB. See here for a full-res extract.
Also, see here for a similar image of Auckland, New Zealand.