What problems can human beings only solve over a very long period of time? And how can we build institutions that solve those problems?

Below is a list of marvellous projects which human beings have undertaken over an exceptionally long time. Many examples contributed by people on Twitter.

The focus is on goal-directed projects (e.g., a scientific experiment or a building), less on more decentralized or unplanned changes (e.g., languages, domestication of livestock, cities, religions). Of course, those are also fascinating, but they have less of a sense of a long-term goal. Jericho is incredible, but the founders probably weren't thinking "I hope this is still here in 9,000 years".

This page is a riff on Patrick Collison's list of /fast projects. There are surprisingly many commonalities with those projects.

A fun question: of these projects, which required a long time, and which could have been greatly accelerated?


  1. In 1998 I went to a talk by Kip Thorne where he said LIGO would likely need a strain sensitivity of "1 part in 10 to the 21" to see anything. That's an accuracy comparable to measuring the distance to the Sun to an accuracy of one atom. I laughed, and thought it would take centuries, at least. In the second sentence of the abstract of the 2016 paper they report a strain sensitivity of 1.0 \times 10^{-21}.↩︎

  2. My office was for many years in the same building as the pitch drop experiment, and I would often walk past it multiple times a day. It has a slow but steady psychological impact in how you think about the space of projects open to you. This is fitting.↩︎