While, therefore, in every civilized country the makers of laws strive to protect private property and private rights from spoliation and abuse, it remains true that extensive municipal and governmental works are more quickly and easily executed in those parts of the world where the legislative authorities have a free hand than they can be under a system of rigid constitutional restraints. Those vast projects which have created the modern city of Paris and are transforming London and many continental cities would necessarily follow different channels in this country; yet there is every reason to believe that the constitutional limitations which here determine the form of public improvements do not really prohibit any measures that in this country would be considered wise. It will be found that the restraints of the fundamental law under which we live do not forbid any of the steps recommended in the proposed Plan of Chicago, although in many important respects they do fix and control the manner in which, and the means by which, these steps can be taken. The state, and its agent, the municipal corporation, are fully empowered to protect and to promote the public welfare, and for that purpose have been vested with the three great functions of government known as the police power, the power of eminent domain, and the power of taxation, in one or another of which will be found adequate authority for the accomplishment of the Plan. The police power has been characterized by the Supreme Court of Illinois as “that inherent plenary power in the state which permits it to prohibit all things hurtful to the comfort, welfare and safety of society.”[32] Avoiding too rigid an exactness of definition, the courts have described it in terms which are said to be summed up in the statement that “the police power, in its broadest acceptation, means the general power of a government to preserve and promote the public welfare by prohibiting all things hurtful to the comfort, safety and welfare of society, and establishing such rules and regulations for the conduct of all persons, and the use and management of all property, as may be conducive to the public interest.”[33] It is only under the police power that men can be required to submit to the destruction or appropriation of their property without monetary recompense for the loss.[34]