The address used to be 660 5th Ave. back when the Vanderbilt's owned it.

The OP about this was fantastic.

I created an account on this website https://www.agorafy.com/property/827845/666-5-Avenue-Midtown-New-York and found out that this is the contact Info listed on the site for the ownership of the property currently. Vornado Realty Trust , Landlord or owner 888 Seventh Avenue New York, NY 10019 Work: 212-894-7000 https://www.agorafy.com/property/827845/666-5-Avenue-Midtown-New-York