I think the most unique feature of Rio de Janeiro is the relationship between the built and natural mountains. Where the natural mountains are the morros, and the built mountains are the collection of skyscrapers. The morros are on a very monumental scale and the built environment seems to replicate and connect to the scale of the mountains. The skyscrapers mimic the height of the morros and the density of the buildings relate to the density of the trees found on the morros. I find the relationship between the built and natural environment an overall theme that should be considered in all designs. Personally, I think the best designs emerge when the architect and landscape architect work in unison on the overall design. Consistent relationships that enhance and build off of one another is something that I think is displayed well in the Ministry of Health and Education Building. The relationship of the trees chosen to compliment and enhance the height of the building results in an overall consistent design. The conditions surrounding the building are just as important as the building itself. If there is one thing that Rio has taught me, it is that the built and natural conditions should always work together to create a masterful work of art. 
I totally agree with this observation! I feel a persistent reflection between the massing and scaling of the morros against the collusion of skyscrapers. I feel like skyscraper collection takes on a few roles, though. In addition to that reflection of the morros you mentioned, it sometimes felt as if the skyscraper zones were pools of built environment that had rolled off the morros into gullies and valleys at their feet. The built environment almost appears to “accumulate” into the spires and stacks of skyscrapers where it is possible to do so on flat ground, then thin itself out as the land becomes steeper, creating the smear of relatively low-rise favelas built up the mountainside.
Also, I wish the architecture of Rio made the same kind of link you have made in the way it thinks about designing. Though we can see the link between these “artificial mountains” and the morros above, I do not believe these accumulations of built density and height were created with that connection in mind. It would be amazing to see complexes or neighborhoods of skyscrapers designed explicitly to reflect the breathtaking natural hills that surround them.