Eratosthenes did something great: through simple geometry, he connected a shadow to the radius of the Earth. When he did that, everybody was able to measure the length of a shadow, while hobody had the faintest idea of the Earth's radius. Seeing a connection between two such, apparently unrelated distances, informing us on such a fundamental and far-reaching question (where we are) is the climax of Science in general and Physics in particular.
Staring September (2021), we are trying, with the IOP, to reproduce this fundamental and enlightening experience of rare historical and civilizational magnitude.