>>Ok, I think this one is actually relatively easy - but I find it interesting nonetheless.
>>
>>Assume that the Eiffel Tower has a mass of 8000 tons, and a height of 300 m.
>>
>>What would be the mass of a model, made to scale - accurate in every detail, and made from the same material - having a height of 30 cm.?
>
>Can we consider Eiffel Tower as cylinder?

Only if it looks to you as cylinder.