Quoting Wikipedia: Ytterby is the single richest source of elemental discoveries in the world; the chemical elements yttrium (Y), terbium (Tb), erbium (Er), and ytterbium (Yb) are all named after Ytterby, and the elements holmium (Ho), scandium (Sc), thulium (Tm), tantalum (Ta), and gadolinium (Gd) were also first discovered there.