  Electromagnetic form factors are fundamental observables that describe the
electric and magnetic structure of hadrons and provide keys to understand the
strong interaction. At the Beijing Spectrometer (BESIII), form factors have
been measured for different baryons in the time-like region for the first time
or with the best precision. The results are presented with examples focus on
but not limited to the proton/neutron, the $\Lambda$, with a strange quark, and
the $\Lambda_c$, with a charm quark.
