This structure is the first that I designed myself and I have challenged myself with this one, as it should not be possible.
When stacking cards you really should go straight up. Higher levels need to be supported with something below it (preferably directly below). With the columns in the Colosseum, there was parts of the upper levels that did not have anything directly below it, but those upper levels were spread over a large area much of which did have columns directly below.
The difference with the tower I am building here is that after the first few levels the rest of the structure is all over the middle of nothing.
I have been in Paris two years ago. The eiffel tower is really an amazing construction. The view on the top is great.