This talk is concerned with the regularity of solutions to parabolic evolution equations.
Special attention is paid to the smoothness in the specific scales $\ B^{r}_{\tau,\tau}, \ \frac{1}{\tau}=\frac{r}{d}+\frac{1}{p}\ $ of Besov spaces. The regularity in these spaces determines the approximation order that can be achieved by fully space-time adaptive approximation schemes.