Ytterby is a village on the Swedish island of Resarö, in Vaxholm Municipality in the Stockholm archipelago. Today the residential area is dominated by suburban homes. The name of the village translates to "outer village". Ytterby is the single richest source of elemental discoveries in the world; the chemical elements yttrium (Y), terbium, erbium (Er), …Ytterby is a village on the Swedish island of Resarö, in Vaxholm Municipality in the Stockholm archipelago. Today the residential area is dominated by suburban homes. The name of the village translates to "outer village". Ytterby is the single richest source of elemental discoveries in the world; the chemical elements yttrium (Y), terbium, erbium (Er), and ytterbium are all named after Ytterby, and five more elements were also first discovered there.