The Sagrada Familia was my first thought too. Definitely worth a visit! I think it very much carries on the spirit of Gothic cathedrals. Those builders used the best construction techniques of their time to create breathtaking buildings, and Gaudí did the same with the techniques of his time (and those who picked up the work after he died did the same). The interior with the tree-like branching columns is especially impressive...
I doubt any of the all-window-facade building will be able to stand the test of time. On the other hand, the parisians wanted the ”useless and monstrous” Eiffel tower torned down after the exhibition (as was the plan) so I think it is inherently difficult to guess.
With modern technology, we could probably take any building and through regular maintenance, keep it forever. On the other hand, we have weapons that can vaporize any man-made structure in an instant.
It is more about how significant it will be in the future, and we don't know. Maybe some random university building will be preserved for centuries because that's where the cure for cancer will be found. Maybe ITER, if it delivers on its promises, it will be of great historical significance, and maybe a bit radioactive. Maybe an airport or train station being built today that will become a major trade hub. An office building that miraculously survives a nuclear war. Some ugly structure that will be seen by generations as the most representative of 21th century art. Anything, really.
Probably a lot of early 20th century homes in towns around the US will be 'preserved' for a long time as it's become too expensive to tear down and build new homes for most buyers. People say that European homes last a long time because they are timber and stucco, but make teardowns expensive enough and with enough permitting issues, any town in a desirable location can be preserved indefinitely!
Technically an extension of a much older building, but I think the glass pyramid of the Louvre in Paris, completed in 1988, is iconic enough that we will want to keep it around. It's also easy and practical to maintain compared to other structures we value.
I often do image searches for cities I'd like to visit. The old European cities are more likely to be photographed from the street level showing the details of individual buildings, while newer cities in the Americas and Asia are usually photographed from afar as a skyline. I think this indicates a change in how we measure the look of a city.
Ornamentation on the 50th floor is hard to see from the street, while a medieval city is mostly flat (2-5 stories) from afar.
Architecturally ornamentation is out and rarely tried now, so individual buildings don't stand out from the street perspective. Rather, the use of monumental forms (China TV building, London's Shard) are what set a building apart from the city now. And indeed the city itself has become a composition via skylines.
So although the buildings we construct now are much more austere than in the past, the city as a whole has acquired a third dimension which is where the originality plays out. So instead of individual structures standing out, entire cities now stand out.
On the subject of glass boxes, I can agree that they are forgettable.
Assuming our society endures, I would say many skyscrapers likely to be preserved, especially the iconic ones, because there are economic reasons to keep them on top of historic ones. Destroying a house to build a larger building makes sense economically, but destroying an already large building to rebuild is less interesting in terms of space gained.
Due do usefulness maybe a few very significant pieces of infrastructure, but I don't there's such a thing as a new sacred structure because there's nothing that is sacred, period. An interesting observation is that artefacts which were moved from their places of origin (which are still sacred) in the ME to say museums as an explicit act of modern conservation, these were the first artefacts to be destroyed during the recent wars in the region, while anything still stuck in its 'unsafe' places has survived. The defining feature of modernity is that everything is replaceable.
Answer: we don't know, but most structures from past centuries are gone and replaced by new buildings on a regular basis, so it would not be surprising that we keep doing the same thing in the future as well, with only very "monuments" kept as tokens of the 21st century.
Probably buildings that gain historical significance - that's a very hard thing to predict but I'd guess the next important site is probably going to be where Ukraine and Russia sign a treat to cease violence - assuming that happens and that it happens on Ukrainian soil.
Some sites of historical significance were intentionally destroyed, particularly if the memory is painful. Most notably it has been very hard to preserve what remains of the Berlin Wall as a memorial.
That's an interesting contrast with places that are important but not honored - I know that some concentration camps have been preserved as museums to the horror but the Berlin wall is kind of a great counter example because not only does the city not want the wall there anymore (obviously)... but Berlin is also specifically opposed to trying to preserve the path of the wall since it'd reinforce the division in the city.
There is, from the Berliners I've spoken too, a strong desire to make sure the memory of what the wall did isn't lost - but all but the most minute physical presences of the wall were actively removed.
> A lot of these Cathedrals managed to survive long period of neglect with minimal to no maintenance.
If by "minimal maintenance" you mean frequent rebuilding after fires, refurnishing, extension of the building and stylistic changes, and almost continuous restoration effort, they you're right, of course.
No, many buildings in this style really were left virtually unmaintained for centuries at a time. The only really essential maintenance is clearing the gutters, and that's only necessary in certain biomes. Of course they needed full refurnishing afterwards, but the shell of a solid stone building is pretty resilient, being, well, solid stone.
> Some of them being Great Wall of China, Taj Mahal, Machu Pichu, Petra, etc.
See:
> Thus, the Lindy effect proposes the longer a period something has survived to exist or be used in the present, the longer its remaining life expectancy. Longevity implies a resistance to change, obsolescence or competition and greater odds of continued existence into the future.[2] Where the Lindy effect applies, mortality rate decreases with time.
Petra was abandoned and rediscovered in the 1800s and has really only emerged in the last 20 years as a destination, after being featured in Indiana Jones movie. Similarly Machu Picchu was abandoned and forgotten only to be rediscovered in 1909.
* https://en.wikipedia.org/wiki/Notre-Dame_de_Paris