The "classic" tapered base shape was part of the original V2 rocket design from World War II. The shape was selected because an engineer from the 1930s had previously calculated that it was aerodynamically optimal. Later rocket designs, including Atlas, Titan, and all of the US's manned space program, abandoned the V2 shape for straight sides, because straight cylinders are considerably easier to manufacture.
I wouldn't want to live in one of the buildings in the background, when that thing takes off.
It's because of NIMBYs like you that I can't commute to the Moon!
The "classic" tapered base shape was part of the original V2 rocket design from World War II. The shape was selected because an engineer from the 1930s had previously calculated that it was aerodynamically optimal. Later rocket designs, including Atlas, Titan, and all of the US's manned space program, abandoned the V2 shape for straight sides, because straight cylinders are considerably easier to manufacture.