delivered the opinion of the court.
We are inclined to assent to the proposition advanced by appellants that a municipality cannot declare a thing to be a nuisance which is not so in fact. But it has no bearing upon the facts in this case, for we think a wooden structure such as this roof stand is shown by the evidence to be, within the fire limits of the city, is clearly a nuisance as it stands, and the defendant, city of Chicago, has the clear right, and it is its duty, to abate the nuisance, unless the acts of its officers which have induced the action of the complainants in constructing the building and the seats on the roof of the building have worked an estoppel on the municipality, by making it inequitable to permit the municipality to stultify itself by retracting what its officers have done.
The doctrine of estoppel in pais applies to municipal corporations only to the extent that it leaves the courts to decide the question by all the circumstances *344of the case and to hold the public estopped or not as right and justice may require. C. & N. W. Ry. Co. v. The People, 91 Ill. 251; Martel v. City of East St. Louis, 94 id. 67; Lee v. Mound Station, 118 id. 304. And it does not apply where the city official has exceeded his authority in issuing a permit in violation of a city ordinance. Burton Co. v. City of Chicago, 236 Ill. 383; Hibbard, Spencer, Bartlett & Co. v. City of Chicago, 173 id. 91.
This brings us to a consideration of the main question in the case, the construction of sections 656, 722, 723, 724 and 725-of the Eevised Municipal Code of Chicago, and their application to the structure of complainants. It is contended on behalf of complainants that section 656 does not apply to the subject-matter of this suit, and that sections 722 to 725, both inclusive, are applicable, and that the permit in this case was applied for and granted under these sections of the code and that these sections govern the construction and use of the structure in question. On behalf of the defendants it is urged that sections 722 to 725 were adopted by the city council in their present form in January, 1901, and that section 656 was adopted by the city council March 20, 1905. Construing these sections together, and giving to each its proper force, the legal effect of section 656 is to limit the application of the other sections to buildings and structures within the fire limits of the city which conform to the provisions of section 656.
This last named section is set out in the answer of the defendants, and its language is broad and comprehensive. “Wooden grandstands or tiers of seats, commonly known and described as grandstands,” is sufficiently general and comprehensive to include all tiers of seats erected on the ground or on roofs for spectatorial purposes within the meaning of section 722, and within the fire limits of the city of Chicago. We find no difficulty in reading and construing section 656 with other sections named. There is no conflict between them, and they should be construed together.
*345It is urged, however, on behalf of complainants, that if section 656 be construed to apply to the structure here in question—a wooden stand erected on the roof of a building—it is an unreasonable ordinance and therefore void. We do not think the ordinance is unreasonable. 'In our opinion it is a valid ordinance. By its terms it applies to structures within the fire limits of the city. It cannot be said that the prohibition against the erection of wooden stands or tiers of seats within sixty feet of any other building or structure within the fire limits is unreasonable, for it is a necessary precaution against the spread of fire. Such structures, if permitted to be erected close together, or close to other buildings, would be the most effective means of spreading a conflagration. As to that part of the section requiring frontage consents, it has been held that requiring such consents does not violate the constitutional maxim, which prohibits the delegation of legislative power by the body upon which it is conferred. City of Chicago v. Stratton, 162 Ill. 494; Patterson v. Johnson, 214 id. 481.
The wooden stand or tiers of seats, which the decree directs the complainants to remove from the roof of their building, were erected, as appears from complainants’ bill and the evidence in the record, about two years after the adoption of section 656 by the city council, and while the ordinance was in full force and effect. Complainants were charged with knowledge of the ordinance and its provisions. They knew that the structure which they proposed to put on the roof of their building would be, when erected, within a few feet of the adjoining building, and they should have known that it was prohibited by the ordinance. As said in J. Burton Co. v. City of Chicago, supra, complainants, in applying for a permit, must have lmown the commissioner had no power to grant it. The permit itself purports to be issued in pursuance of the ordinances of the city. The issue of the permit gave no right to complainants because the commissioner who *346signed it was without authority to issue it. He was prohibited from issuing the permit by the ordinance. “Every person is presumed to know the nature and extent of the powers of municipal officers, and therefore cannot be deemed to have been deceived or misled by acts done without legal authority.” Seeger v. Mueller et al., 133 Ill. 86, 95; City of Danville v. Danville Water Co., 178 id. 299; City of Chicago v. Williams, 182 id. 135.
It follows logically from the principles laid down by the above cited cases that no estoppel can ordinarily arise from the act of a municipal corporation or officer done in violation of or without authority of law. When such acts are performed under authority of law another question arises. But, in either case, where the principle of an estoppel in pais is applicable it is for the courts to decide the question, as we have seen, and to hold the public estopped or not as right and justice may require.
On the question of right and justice as between the parties to this controversy, we are unable to discover any quality of justice or equity in complainants’ position. They come into a court of equity as violators of ordinances designed and adopted to protect life and property, and ask the court to grant them equitable relief against the public authorities whose duty it is to enforce such laws and regulations for the protection of the public. Complainants by their bill show that to the extent of preparing and using their property for spectatorial or amusement purposes, where large numbers of people are invited to congregate upon the payment of admission fees, they have devoted their property to a public use; and by that act they have in effect given to the public authorities the right to regulate the use of the property for such purpose. Under such circumstances it does not rest with them to come into a court of equity and ask that the general regulations of the municipal authorities applicable to private property *347devoted to such purposes shall not be enforced against them, where there are elements of danger to the lives and limbs of the occupants of such property. As against the efforts of the public authorities to enforce reasonable regulations designed to protect the public who may be induced to patronize such an establishment, complainants have no standing in equity.
In view of the evidence in the record showing elements of danger in the structure, entirely apart from any weakness in the building or the stand which rests upon it, showing increased fire hazard, insufficent means of exit, danger of panic on account of the height of the structure, and a clear violation of valid city ordinances, the Circuit Court was right in denying to complainants any relief under their bill of complaint. And in view of the fact that complainants broug’ht the whole matter into a court of equity, we see no reason why the court should not decree that to be done which ought to be done, and,order the structure, which is a constant and continuing menace to life and property, to be removed, without remitting the parties to proceedings at law.
The decree is affirmed.
Affirmed.