Sometimes I don't think we realise or appreciate just how old things are and how they've survived through consistent and conscious effort. A century is beyond the lifetime of most people. A lot of similar-style public transport in the US was practically killed between 1920-1940 with the dawn of the car.

In the UK you might live in a house that is 100 years old, and in London you take a tube train through a tunnel carved out 120 years ago, or something. But it rarely registers that you are using what we in tech would consider way beyond a relic.

Your automated train on the Victoria line was done in the 60s or 70s, the DLR (similarly automated) a decade later. They were so weird at the time that, story has it, the drivers couldn't read a paper in the cabin because it freaked passengers out. Despite the fact they weren't in direct control. Still, automated is weird and it's half a century old.

So what does this say about other historical events that are slipping beyond our collective conscious, like the two world wars? Or even something like 9/11 where there is a whole generation who never saw that?

And what does it say about knowledge? What we keep in our awareness and what we pass on to historians?