The 57-year-old tower at 270 Park Avenue is not some ordinary skyscraper. Opened in 1961 as the headquarters of the old Union Carbide company, preservationists say it's an important piece of mid-century modern architecture. 

"It's a building by one of our most prominent modern architecture firms, Skidmore, Owings & Merrill, and it's one of the few buildings designed by a female architect, Natalie De Blois," said Daniel Allen of the Historic Districts Council.

But now the building's owner, JP Morgan Chase, wants to replace the 52-story tower with a 70-story skyscraper. The move is the direct result of new zoning rules in East Midtown that allow developers to build higher as long as they fund public improvement projects. Preservationists worry the demolition would be a taste of what's to come. 

"Everything becomes too valuable -- even this remarkable piece of American history," Allen noted.

Prior to the rezoning, City Planning documents called the tower "one of the city's greatest modern buildings." But efforts to landmark it fizzled. The Landmarks Preservation Commission points out that it has landmarked 50 other buildings in the area, including some designed by the Union Carbide Building's architects. 

Supporters say demolishing this building is not just important to JP Morgan Chase but also to the de Blasio administration's efforts to modernize this business district.  

Chase says the current building is too small for its workforce. The man who helped to write the rezoning plan says if Chase were to build elsewhere in the city it would be a blow to Midtown. 

"JP Morgan's decision on where it would locate was perhaps the most important decision that would determine the future of East Midtown, and this is now a very positive development," said Carl Weisbrod, former NYC Planning Commission Chairman.

But preservationists say the de Blasio administration needs to think more about saving the city's history. 

"I think preservation is not a priority of this administration," said Tara Kelly of the Municipal Arts Society.

They warn that if Chase does not change its mind, they will look at legal options to save the building.

If it is torn down, it would make history as the tallest building ever to be voluntarily demolished.