Shadowgraph movie obtained in water in a Rayleigh-Bénard cell with smooth plates. The Rayleigh number, $\mathrm{Ra}$, is of order ${10}^{10}$, where

$\mathrm{Ra}=\frac{g\alpha \mathrm{\Delta T}{H}^3}{\nu \kappa }$.

This video was taken during the 2018 “laboratory practicals” of the ENS de Lyon batchelor students Timothée Bonnefoi, Blandine Simon and Pascal Wang.