Two things give it away. One, the blurred foreground. Two, the entire strip of people are of the same size.
If you use a true wide angle lens to take this shot, you will get the same shot, but much smaller, if you shoot from the same spot; or if you go closer (beyond the water), the people on the left will look much bigger.
I find that when taking a subject that spans the film format, a telephoto shot looks more natural. A wide angle make it less real with its distortion.