In an inventory of the agencies which might be capable of sharing in the creation of outer parks and boulevards, mention should not be omitted of a Greater City of Chicago, which might be invested by the legislature with power to purchase or condemn land far beyond its own corporate limits in order to establish a system of parks and boulevards commensurate with the needs of its inhabitants.[41] Some doubt has been suggested as to the constitutionality of such a grant of power if attempted under the so-called Chicago charter amendment to the state constitution,[42] which authorizes “a special charter of local municipal government for the territory now or hereafter embraced within the limits of the city of Chicago.” The effective policing by the city of parks and boulevards outside the city limits would present practical difficulties, and the plan would impose upon the city the entire cost of improvements in the advantages of which the suburban districts in which these improvements were located would share. If all of the people and property benefited are to bear their proportionate share of the expense, the proposed system of outer parks and boulevards should be acquired and controlled by the county or by a new municipal body. CITY PARKS, SQUARES, BOULEVARDS, AND AVENUES The existing municipal corporations that might be authorized to bear a part in realizing the Plan within the city limits are the city of Chicago, the county of Cook, and the several park boards. Any participation by the Sanitary District, as by bridging its canals or improving the appearance of their banks, would be incidental.