Why would it need to be 1.2 miles deep? at that point, the floor no longer 26 feet below sea level, but 1.2 miles below.
The builders may not account for the curve, but if they are digging relative to sea level., then they never have to. If throughout the whole stretch of the canal the depth is 26 feet, then the base of it actually is curved without them even intending it to be.
Assuming the container is flat along the top and bottom, the water wouldn't be parallel with the rim of the glass.
As far as the "hump" is concerned, it would be a constant arc. Where the peak of the hump is depends on the position of the glass container.
I would say if anyone important did. Russia, China, Japan, and others all have sent crafts to the moon, including rovers. If the US didn't land on the moon, then one of these space programs could easily find where the US allegedly landed and refute it. And yet, nothing.
If any of them were to make a case disputing the US moon landing it would be incredibly simple (if the US never landed on the moon).
Sea level is relative to the center of the earth though, not the surface of the land. So sea level actually does have a curve
Not sure what footage you're talking about, so I can't really say whether or not I believe it.