For an engineer who likes the world of aeronautics, the V12 helicopter case is worth noting. I have obtained the information from an article written by Kyle Mizokami in POPULAR MECHANICS magazine and I thank him very sincerely for his contribution.
For those who do not know, the V12 helicopter was created by the Russians in the 1960s (at the height of the Cold War) and made its first flight in 1968. It was enormous in size (larger than a current Boeing 737 aircraft), It was supported by two rotating blades and was capable of moving almost 40 tons of weight or almost 200 passengers.
It was presented internationally at the Paris Air Show in 1971, being the surprise of all the attendees. It was huge for that time, and also for today, since no such large helicopter has ever been built again.

This was a product of the cold war, and according to some experts the idea of the Russians was to use this helicopter to transport and hide their ballistic missiles in the Siberian lands. Who knows ?
The truth is that only two prototypes were made and a few years later the project was cancelled.
You can see a very interesting and really worthwhile video at: https://youtu.be/yOApFeEgHcE
With my reflection today, apart from paying tribute to all those who worked on this project and made a product that was very advanced for its time (60 years ago now), it is to remember that for a project to be successful, it must respond to a real need of society. And I say real need, not imaginary.
One of the problems of dictatorial governments is that they can decide to undertake projects that their society does not need, and sooner rather than later they end up failing and also consuming resources that could be used in other more beneficial projects.
And I am reminded at this moment of the missile projects of the North Korean government.
To finish I want to thank Kyle Mizokami again for his articles in POPULAR MECHANICS magazine in which he demonstrates a high degree of professionalism and experience. Thank you.