We were standing on a rocky beach at the outskirts of Toronto looking south. This is the northern shores of Lake Ontario. If the earth were flat, we should be able to see the USA cities of Buffalo and Rochester. As it was, we were looking at the clean, straight line of the horizon. Looking carefully, you should be able to see a line of geese flying just above the water. Seconds later, the geese would flop down on the water, perhaps attracted by a school of fish.
Such a view is available to anyone who cares to come down to the waterfront in Toronto, where most days are clear. In my secondary school days, on Saturday afternoons, we used to climb the hill where the Ocean Park in Hong Kong is, and looked at the horizon to the south. Now, the hill is off-limits. Even if you can climb up there, all you can see would be just a gray blurry mist. The line between the sky and the water is no longer visible. We have lost a lot in the pursuit of progress.