Back in the olden days, people started building really tall buildings called skyscrapers. But, in big cities like New York, these buildings were getting so tall that they were blocking out the sun and causing problems for the people living and working nearby.
So in 1910, the government made a law called the Height of Buildings Act that said how tall buildings could be in different parts of the city. Basically, it said that buildings couldn't be taller than a certain number of stories or feet in certain areas. The law helped make sure that everyone had access to sunlight and fresh air, and that the tall buildings didn't cause any more problems.