A construction crane dropped a massive heating and air-conditioning unit nearly 30 stories at a Midtown Manhattan building Sunday, injuring 10 people.

The unit was to be lifted through a hole on the 30th floor, but it came crashing down, shattering a part of the building's facade, officials and witnesses said.

The massive load landed in the middle of Madison Avenue near East 38th Street, sending a shower of debris and broken glass on the streets.

"It sounded like a freight train," said Milo Avidane, who watched the crash from his apartment across the street, according to Fox News.

"They were rigging the HVAC unit through a hole on the top floor, and it never made it into the building," Avidane added. "Either the cables gave out or the something... and it landed smack in the middle of Madison - right in front of the restaurant on the bottom floor."

Mayor Bill de Blasio addressed the incident, saying, "Thank goodness this occurs at this hour, on a weekend, when there were not many people around," The New York Post reported.  

"Obviously, this is a very serious incident," de Blasio added. "There will be a full investigation."

No life-threatening injuries have been reported, Pix 11 noted.

Several streets along Madison from 37th to 39th were evacuated due to fears of the building's facada collapsing, The NY Post reported.

"We lucked out on this," one official said.