![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNoyJT6blPrRmMjKcGD2V2WBC-JtKh6umvoJsuOKYcIcutKmLz4n8WXIRNwKP6H7ImrZgemo9NmBumJq2mrvt13u_M7j2pXh06jLR24DxNkj8KiD4cZH9LzTRECOsJuAu_GoGpShTTSS0N/s320/New+York6.jpg)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEja5urRtrxuMwqnHAXKsg3yjIezhq0__Qdci68xYChU5GPd1tMaQGNWZMqQabNzCUzM2M8AHnOflL5riOPYdMHBL9BMobpY9uTMkqB8sMV7cTxOhOoUSlX4z0zfQd6RdPrOYr0v8-NbHzYY/s320/New+York8.jpg)
Of note, the slanted top contains a huge block of concrete
to keep the building from swaying in the wind. It was
added after the tower was constructed in the 70's.
It is called a Tuned Mass Damper.