Mass. Gen. Laws ch. 45, § 15: Playgrounds for minors

Section 15. Every town having a population of more than five thousand which accepts this section, and every city and town having such population which has accepted corresponding provisions of earlier laws, shall provide and maintain at least one public playground conveniently located and of suitable size and equipment, for the recreation and physical education of the minors of such city or town, and at least one other playground for every additional twenty thousand of its population.