The good: Helicopters
Helicopter rotors work in similiar way as the seeds of a maple tree. The key concept here is called autorotation which (theoretically) prevents the aircraft from stalling.
Early drawings of a helicopter date back to concepts by Leonardo da Vinci in the 1480s and since then many people tried to built such an aircraft thus it is hard to say who should be called “the” creator.
Why I like it
The concept of a helicopter demonstrates a useful application of biomimicry as it provides some kind of safety to the crew if the engine stops working.
The bad: Eiffel tower
The Eiffel tower has been built as the entrance arch to the 1889 World Fair in Paris. It mimics the head of the thigh bone due to a unique structure supporting the weight of the body by bones in the leg.
Gustave Eiffel has built the Eiffel Tower based on the original design by Maurice Koechlin and Émile Nouguier.
Why I don’t like it
The construction of the Eiffel Tower has been ahead of its time but I cannot see a deeper meaning in constructing a steel tower without any beneficial function to humans / society (except the later addition of antennas which was not the intention of building it).