In Keen v. Mayor & City Council of Havre de Grace, 93 Md. 34, 48 A. 444 (1901), a pedestrian was injured when he fell into a hole on a City sidewalk. Concluding that the evidence of negligence was legally sufficient to submit the case to the jury, the Court said: Before ... the municipality can be made liable in any case, it must be shown that it had actual or constructive notice of the bad condition of the street.... "By constructive notice is meant such notice as the law imputes from the circumstances of the case. It is the duty of the municipal authorities to exercise an active vigilance over the streets; to see they are kept in a reasonably safe condition for public travel. They cannot fold their arms and shut their eyes and say they have no notice. After a street has been out of repair, so that the defect has become known and notorious to those traveling the streets, and there has been full opportunity for the municipality through its agents charged with that duty, to learn of its existence and repair it, the law imputes to it notice and charges it with negligence." If the defect be of such a character as not to be readily observable, express notice to the municipality must be shown. Id. at 39 . Applying the principles set forth above to the facts of the case, the Court concluded, id. at 40: It is sufficient to state that divers witnesses testify to the existence and character of the hole. Mrs. Suter said she had seen it there for thee weeks before the accident; George Carroll, that it had been there, "maybe, a couple of weeks or so"; and John Suter, "two or three weeks." There is further proof that the hole was in the bed of the sidewalk, and not hidden or obscured by anything from the full view of any one who passed along that part of the walk. There was also evidence that the plaintiff passing there on a dark night, without knowledge of the defect, stepped into the hold, and "was thrown backward" and fell into the gutter, and thereby was injured. If the jury believed this testimony, they would unquestionably be justified in finding that the municipality was negligent in not repairing the defect, if it, or its proper officers or agents, knew of its existence; and if they did not have knowledge of its existence then they did not exercise that active vigilance which was incumbent on them, to see that the sidewalk was kept in a reasonably safe condition for public travel.