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

I think a bit of it is survivorship bias, if I have built 1000 buildings, and 10 of them are left standing 2000 years from now, that means 1% are still standing and 99% fell, doesnt seem that unrealistic. Some buildings will leave a better foundation by chance, some will not get hit by an earthquake etc. But we look at the 10 buildings that are still standing and be amazed.