
A universal cover in ℝⁿ is a convex set that can cover every set of diameter 1. Lebesgue asked in 1914 what the minimum area of a universal cover in ℝ² is. I shall present my study of the minimum volume V of a universal cover in ℝ³, showing that 0.545 < V < 0.656, improving a previous result by G. Kuperberg in 1999.