This is a good one, below is quoted from this article

"The researchers calculated the mass of New York buildings and determined their downward pressure on the Earth. They also presented satellite-image evidence of gradual sinking caused by the city’s impressive structures.

The buildings in New York weigh 1.68 trillion pounds total, according to the researchers — a mass that The Guardian equated to 140 million elephants (presumably the large African kind)."

End of quote. (bold added to highlight the other measurement system)

They are looking for solutions to help stop the sinking of the buildings. I may have to suggest they fill all of the buildings with HELIUM to make them lighter!!!!