1717 Broadway, a new hotel development that has the distinction of being the tallest in the Western Hemisphere, has topped out at a lofty 750-feet, the tower’s developer Granite Broadway Development and its construction manager CNY Builders announced on Thursday. The building will house a Marriott Courtyard on the lower floors and a 261-unit extended stay hotel at the top that will also be operated by Marriott. As its height suggests, it will permit its guests impressive views of the city. But in the dog-eat-dog world of New York City real estate, so too will the building, which already is distinct for the way its thin profile dramatically contrasts with its soaring height, also stand in the way of such ogling from the upper floors of its neighbors. 1717 Broadway will obstruct to a degree the eastward views for 250 West 55th Street, a new office tower just a block west that is in the process of being developed by Boston Properties. The situation is not the first time a new tower has been built only to have its views usurped by – or be the usurper of – a rival’s. There is a ruthless math to tower development in Manhattan and the addition of one building to the skyline almost always subtracts from the views of another. In the slideshow that follows, The Commercial Observer examines similar view-blocking rivalries that have cropped up in the city over the years.