In July 1959, the creation of the Blue Line restricted water lines from being extended beyond an elevation of 5,750 feet. In November of 1967, Boulder made history by passing the nation’s first voter-approved sales tax for open space and the creation of the Greenbelt. Another critical vote was passed when, in 1971, a 55-foot building height limit was set, ensuring views of the foothills and Flatirons will always endure. A historic preservation code was passed in 1974 and a residential growth management ordinance in 1976. Today, Boulder has preserved the largest per capita of open space in the country—over 45,000 acres and 148 miles of trails within the city. With your help, we will continue this legacy and keep Boulder Open Space forever open.