@constancegrady has an article out on Vox that puts the value of Notre Dame in perspective. She focuses on a passage by Victor Hugo in his book "The Hunchback of Notre Dame," published in 1831. The book became very popular and resulted in public pressure to restore the deteriorating Notre Dame cathedral.
The passage reads like a definition of the best of architecture and art:
Great edifices, like great mountains, are the work of centuries. Art often undergoes a transformation while they are pending, pendent opera interrupta; they proceed quietly in accordance with the transformed art. The new art takes the monument where it finds it, incrusts itself there, assimilates it to itself, develops it according to its fancy, and finishes it if it can. The thing is accomplished without trouble, without effort, without reaction,— following a natural and tranquil law. It is a graft which shoots up, a sap which circulates, a vegetation which starts forth anew. Certainly there is matter here for many large volumes, and often the universal history of humanity in the successive engrafting of many arts at many levels, upon the same monument. The man, the artist, the individual, is effaced in these great masses, which lack the name of their author; human intelligence is there summed up and totalized. Time is the architect, the nation is the builder. […]
All these shades, all these differences, do not affect the surfaces of edifices only. It is art which has changed its skin. The very constitution of the Christian church is not attacked by it. There is always the same internal woodwork, the same logical arrangement of parts. […] The service of religion once assured and provided for, architecture does what she pleases. Statues, stained glass, rose windows, arabesques, denticulations, capitals, bas-reliefs,—she combines all these imaginings according to the arrangement which best suits her. Hence, the prodigious exterior variety of these edifices, at whose foundation dwells so much order and unity. The trunk of a tree is immovable; the foliage is capricious.
It took 200 years to build Notre Dame. Great examples of Vietnamese modernist architecture, like the Independence Palace, took only a few years, but the level of art and the value of the architecture is comparable to a degree.