How the Pantheon, which was built over 2000 years ago, is still standing when buildings made 150 years ago are about to crumble.

Question

Edit- After reading most of the comments the general consensus is listed below:

1. The unique composite matrix of the concrete used gives it a self-healing property. When cracks form in the concrete, it will naturally seal them.
2. The Pantheon was a very significant structure which led to meticulous maintenance and restorations
3. The Romans didn’t have modern engineering. So they didn’t know exactly how strong they’d have to build the Pantheon to make it last. Their solution was to overbuild the hell out of it.
4. Survivorship bias. There were thousands of buildings constructed by the Romans but very few remain which are the ones we marvel at.

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In: 564

Answer 1

Fun fact that no one will care about: a lot of Roman and Greek ancient buildings (ex. The Colosseum) are so decayed not because of poor engineering or lack of maintenance, but because they were literally dismantled to get marble and other materials to build new buildings.

Or because they were bombed during WWII, an occurrence that ancient Romans obviously didn’t think about.

That’s also the reason why a lot of medieval buildings are still standing, because they were not made with pricey materials but built well enough to survive centuries.

Imagine being the Pope and going like: “need marble? Just take it from the Colosseum, no one cares about that old sh*t”